Extensible Business Reporting Language (XBRL) 2.1
RECOMMENDATION - 2003-12-31 + Corrected Errata - 2005-04-25
This version:
XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2005-04-25.htm
is a non-normative version of this specification. The NORMATIVE version is in the file
http://www.xbrl.org/Specification/XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2005-04-25.rtf
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Name |
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Phillip Engel |
KPMG LLP |
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Walter Hamscher[1] |
Standard Advantage |
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Geoffrey Shuetrim |
KPMG LLP |
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David vun Kannon |
KPMG LLP |
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Hugh Wallis |
Standard Dimensions (formerly of Hyperion Solutions Corporation) |
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Name |
Contact |
Affiliation |
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Charles Hoffman |
UBmatrix |
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Campbell Pryde |
KPMG LLP |
This document is an update to the RECOMMENDATION document dated 2003-12-31 and incorporates all errata corrections that have been approved by the XBRL International Specification Working Group as of the date of publication. The International Steering Committee of XBRL International approved this document for publication as an update to the RECOMMENDATION on 2005-04-25.
Each erratum correction is listed in Appendix D but in this version there is no indication of the details of the corrections since the “track changes” mechanism used to identify those details has had “all changes accepted”. The details of the changes will be found by examining the version marked as “redlined”. Links to discussions surrounding these corrections are included but it should be noted that some of these are to “members only” mailing lists. Readers are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.
While excerpts from XBRL schemas are given throughout this document the complete normative versions of the schemas are included in Appendix A. Non-normative versions are also available as separate .xsd files from www.xbrl.org, the XBRL International web site. The (non-normative) schema maintenance mechanism for schemas on the web is briefly described in Appendix A of this document.
XBRL is the specification for the eXtensible Business Reporting Language. XBRL allows software vendors, programmers, intermediaries in the preparation and distribution process and end users who adopt it as a specification to enhance the creation, exchange, and comparison of business reporting information. Business reporting includes, but is not limited to, financial statements, financial information, non-financial information, general ledger transactions and regulatory filings, such as annual and quarterly reports.
This document defines XML elements and attributes that can be used to express information used in the creation, exchange, and comparison tasks of business reporting. XBRL consists of a core language of XML elements and attributes used in XBRL instances as well as a language used to define new elements and taxonomies of elements referred to in XBRL instances, and to express constraints among the contents of elements in those XBRL instances.
1.3 Relationship to other work
1.6 Namespace prefix conventions
2 Changes from the previous published version
2.2 Changes in XBRL taxonomies
3.1 Overview of XBRL taxonomies
3.2 Overview of XBRL instances
3.3 Data integrity and confidentiality
3.5.1.1 The xlink:type attribute on simple links
3.5.1.2 The xlink:href attribute on simple links
3.5.1.3 The xlink:role attribute on simple links (optional)
3.5.1.4 The xlink:arcrole attribute on simple links (optional)
3.5.1.5 The xml:base attribute on simple links (optional)
3.5.2.1 The id attribute on linkbase elements (optional)
3.5.2.2 The xml:base attribute on linkbase elements (optional)
3.5.2.3 Documentation elements in linkbase elements (optional)
3.5.2.4 The roleRef element (optional)
3.5.2.5 The arcroleRef element (optional)
3.5.3.1 The id attribute on extended links (optional)
3.5.3.2 The xlink:type attribute on extended links
3.5.3.3 The xlink:role attribute on extended links
3.5.3.4 The xml:base attribute on extended links (optional)
3.5.3.5 Documentation elements in extended links (optional)
3.5.3.6 Titles in extended links (optional)
3.5.4 Use of XPointer in URI fragment identifiers
4.1.1 The id attribute on xbrl elements (optional)
4.1.2 The xml:base attribute on xbrl elements (optional)
4.2 The schemaRef element in XBRL Instances
4.2.1 The xlink:type attribute on schemaRef elements
4.2.2 The xlink:href attribute on schemaRef elements
4.2.3 The xlink:arcrole attribute on schemaRef elements (optional)
4.2.4 The xlink:role attribute on schemaRef elements (optional)
4.2.5 The xml:base attribute on schemaRef elements (optional)
4.3 The linkbaseRef element in XBRL instances 43
4.3.1 The xlink:type attribute on linkbaseRef elements
4.3.2 The xlink:href attribute on linkbaseRef elements
4.3.3 The xlink:arcrole attribute on linkbaseRef elements
4.3.4 The xlink:role attribute on linkbaseRef elements (optional)
4.3.5 The xml:base attribute on linkbaseRef elements (optional)
4.4 The roleRef element in XBRL instances (optional)
4.5 The arcroleRef element in XBRL instances (optional)
4.6.1 The contextRef attribute
4.6.3 Usage of precision and decimals attributes
4.6.4 The precision attribute (optional)
4.6.5 The decimals attribute (optional)
4.6.7 Definitions pertaining to accuracy
4.6.7.1 “Correct to n Significant Figures”, “Rounding” and “Truncation”
4.6.7.2 “Correct to n Decimal Places”
4.7.3.2 The segment element (optional)
4.7.4 The scenario element (optional)
4.8.4 The unitNumerator and unitDenominator elements
4.10 Equality predicates relevant to detecting duplicate items and tuples
4.11.1 The footnoteLink element
4.11.1.1 Locators in footnoteLink elements
4.11.1.3 The footnoteArc element
5.1.1.1 The periodType attribute
5.1.1.2 The balance attribute (optional)
5.1.3 Defining custom role types – the roleType element
5.1.3.2 The id attribute on roleType elements (optional)
5.1.3.3 The definition element in roleType elements (optional)
5.1.3.4 The usedOn element in roleType elements
5.1.4 Defining custom arc role types – the arcroleType element
5.1.4.1 The arcroleURI attribute
5.1.4.2 The id attribute on arcroleType elements (optional)
5.1.4.3 The cyclesAllowed attribute
5.1.4.4 The definition element on arcroleType elements (optional)
5.1.4.5 The usedOn element on arcroleType elements
5.2.2.1 Locators in labelLink elements
5.2.3 The referenceLink element
5.2.3.1 Locators in referenceLink elements
5.2.3.3 The referenceArc element
5.2.4 The presentationLink element
5.2.4.1 Locators in presentationLink elements
5.2.4.2 The presentationArc element
5.2.5 The calculationLink element
5.2.5.1 Locators in calculationLink elements
5.2.5.2 The calculationArc element
5.2.6 The definitionLink element
5.2.6.1 Locators in definitionLink elements
5.2.6.2 The definitionArc element
xbrl-instance-2003-12-31.xsd (normative)
xbrl-linkbase-2003-12-31.xsd (normative)
xlink-2003-12-31.xsd (normative)
B. Document history and acknowledgments (non-normative)
C. Intellectual property status (non‑normative)
D. Errata Corrections incorporated in this document
Table 1. Terms and definitions.
Table 2. Roles in the linkbaseRef element
Table 3. Unit restrictions based on item types.
Table 4. Equality predicate definitions.
Table 5. Correct signage in an XBRL instance. 79
Table 6. Constraints among the balance attribute and calculation arc weights
Table 8. Standard label role attribute values.
Table 9. Reference role attribute values.
Example 1. A skeletal linkbase
Example 2. One-to-One arc relationships [XLINK]
Example 3. One-to-Many arc relationships [XLINK]
Example 4. Many-to-Many arc relationships [XLINK]
Example 5. Correct use of arcs according to [XLINK]
Example 6. Prohibiting and overriding relationships
Example 7. Example xlink:href values
Example 8. Use of xbrl as the root element
Example 9. A numeric fact with three significant digits
Example 10. A non-numeric item
Example 11. Precision and lexical representation
Example 12. Decimals and lexical representation
Example 13. Lexical representation, precision and decimals
Example 15. Correct to n decimal places. 52
Example 17. Entity identifiers
Example 18. Using the segment element
Example 19. Use of the scenario element
Example 20. Use of the unit element
Example 21. Simple and complex unit of measure comparison
Example 22. Defining a tuple as a member of the substitutionGroup "tuple"
Example 23. Elements describing business properties held and disposed
Example 24. Hierarchy in a tuple
Example 25. Duplicate items, tuples and contexts
Example 26. Predicates for detecting duplicates
Example 27. A footnote in an XBRL instance
Example 28. A skeletal taxonomy schema showing linkbase references
Example 29. Typical element definitions in a taxonomy schema
Example 30. Instant and duration concept definitions
Example 31. Using the balance element to indicate normal debit and credit balances
Example 32. A concept appearing with positive and negative values in an XBRL instance
Example 33. Deriving an enumerated item type
Example 34. Representing fractions
Example 35. Defining a custom role type
Example 36. Defining a custom arc role value
Example 37. Using relationship prohibition to insert a new sub-total into a calculation network
Example 39. Elements of a financial reporting taxonomy
Example 40. Hierarchy in a calculation linkbase
Example 41. Hierarchy of general-special arcs in a definition linkbase
Example 42. Hierarchy in a presentation linkbase
Example 43. Label resource examples
Example 44. Arc between a concept and one of its labels
Example 45. Sample values of xlink:role for several referenceLink elements
Example 46. Arc between a concept and supporting references
Example 47. Reference resource
Example 48. A presentation arc
Example 49. An abstract concept definition
Example 50. Calculations involving decimals and precision
Example 51. Syntax of a calculationArc
Example 52. Cash, equivalent to cash as totalled by branch location and account type
Example 53. XBRL instance fragment with nested tuples
Example 54. A general-special arc
Example 55. Inference of values for non-numeric items with concepts connected by essence-alias arcs
Example 56. Inference of values for numeric items with concepts connected by essence-alias arcs
XBRL is the specification for the eXtensible Business Reporting Language. XBRL allows software vendors, programmers and end users to enhance the creation, exchange, and comparison of business reporting information. Business reporting includes, but is not limited to, financial statements, financial information, non-financial information and regulatory filings such as annual and quarterly financial statements.
This document defines XML elements and attributes that can be used to express information used in the creation, exchange and comparison tasks of business reporting. XBRL consists of a core language of XML elements and attributes used in document instances. Abstract elements in this core language are replaced by concrete elements in XBRL instances. These abstract elements are defined in taxonomies. XBRL consists of a language used to define new elements and taxonomies of elements referred to in document instances and the relationships between taxonomy elements.
All parts of this document not explicitly identified as non-normative are normative. In the event of any conflict or apparent conflict between the English language text of this document and/or schema fragments included in the main body of this document and the normative schemas contained herein (Appendix A), the more restrictive interpretation that is possible from the information provided by the English language text and that provided by the normative schemas (Appendix A) SHALL prevail. The schema fragments incorporated into the body of the text are non-normative and are generally indicated as such by means of shading such as that defined in section 1.1. It is important to note that the normative schemas (Appendix A) do not necessarily always provide the most restrictive interpretation, either because it is not possible to express certain limitations using the syntax of XML Schema [SCHEMA‑1] [SCHEMA-2] or because, as at the time of publication of this specification, some commonly available commercial implementations of XML Schema do not implement otherwise necessary features correctly or fully. For example, the schema specification of the abstract element tuple (Appendix A) does not restrict its content model as much as the English language text in section 4.9. The text of section 4.9 SHALL prevail in this case. Another, converse, example is the order of the sub-elements of the context element. In this case the schema (Appendix A) dictates a specific ordering of these sub-elements yet this is not explicitly articulated in the text of section 4.7. The schema (Appendix A) provides the more restrictive interpretation and thus it SHALL prevail over any alternative possible interpretation of the English language text in this case.
The schemas and other documents published separately and contemporaneously with the specification are non-normative and are provided for the convenience of users of this specification.
The following highlighting is used to present non-normative technical material in this document:
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The following highlighting is used for non-normative commentary in this document:
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Non-normative editorial comments are denoted by indentation and the prefix “NOTE:”:
NOTE: This is a non-normative editorial comment.
Italics are used for rhetorical emphasis only and do not convey any special normative meaning.
The XBRL specification is intended to benefit four categories of users: 1) business information preparers, 2) intermediaries in the preparation and distribution process, 3) users of this information and 4) the vendors who supply software and services to one or more of these three types of user. The overall intention is to balance the needs of these groups creating a standard that benefits to all four groups.
The needs of end users of business information have generally taken precedence over other needs when it has been necessary to make specification design decisions that might benefit one community at the expense of another.
A major goal of XBRL is to improve the business report product. It facilitates current practice; it does not change or set new accounting or other business domain standards. However, XBRL should facilitate changes in reporting over the long term.
XBRL provides users with a standard format in which to prepare reports that can subsequently be presented in a variety of ways. XBRL provides users with a standard format in which information can be exchanged between different software applications. XBRL permits the automated, efficient and reliable extraction of information by software applications. XBRL facilitates the automated comparison of financial and other business information, accounting policies, notes to financial statements between companies, and other items about which users may wish make comparisons that today are performed manually.
XBRL facilitates "drill down" to detailed information, authoritative literature, audit and accounting working papers. XBRL includes specifications for as much information about the reporting entity as may be relevant and useful to the process of financial and business reporting and the interpretation of the information.
XBRL supports international accounting and other standards as well as languages other than the various dialects of English.
XBRL is extensible by any adopter to increase its breadth of applicability, and its design encourages reuse via incremental extensions. For example, XBRL specifies the format of information that would reasonably be expected in an electronic format for securities filings by public entities. XBRL facilitates business reporting in general, and is not limited to financial and accounting reporting.
XBRL focuses on the genuine information needs of the user and adheres to the spirit of reporting standards that avoid the use of bold, italics, and other stylistic techniques that may distract from a true and fair presentation of results. Therefore, there is no functional requirement that XBRL documents support any particular text formatting conventions.
The purpose of XBRL instances is the transmission of a set of facts. There is no constraint on how much or how little they contain. A single fact can form the entire content of a valid XBRL instance, for example, when the information being conveyed is limited to what “Cost of Goods Sold” was last quarter or an XBRL instance can be a database dump, containing huge numbers of facts. It can also be anything in between. This provides a great deal of flexibility and is meant specifically to achieve the goals of allowing XBRL to be reused within other specifications and for application software needing to extract data from otherwise arbitrarily formatted documents. It is expected that, for most uses of XBRL, many XML XBRL instances will be created that consist almost exclusively of facts.
XBRL uses several World Wide Web Consortium (W3C) recommendations, XML 1.0 [XML], Namespaces in XML [NAMESPACES], and refers directly to XML Linking[XLINK] and others listed in Section 6 References. It also relies extensively on the XML Schema [SCHEMA‑1] and [SCHEMA-2] recommendation.
Discussions have taken place with other bodies issuing XML specifications in the financial arena, including OAG (Open Applications Group), OMG (Object Management Group), FpML (Financial Products Markup Language), finXML (Financial XML), OFX/IFX (Open Financial Exchange) and ebXML (e-Business XML). The scope of XBRL does not include transaction protocols. It includes financial reporting and contemplates extensive detail in the representation and use of accounting conventions, which distinguishes it from these other efforts.
The terminology used in XBRL frequently overlaps with terminology from other fields, and the following list is provided to reduce the possibility of ambiguity and confusion (see also the references in section 6 below).
Table 1. Terms and definitions.
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Term |
Definition |
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An element for which the attribute abstract in its XML schema declaration has the value "true" and which, therefore, cannot be used in an XML instance. |
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The concept at the “to” end of a definition arc with arc role http://www.xbrl.org/2003/arcrole/essence‑alias. Alias and essence concepts are definitionally equivalent in the sense that valid values for an alias concept are always valid values for essence concepts to which they are related by an essence-alias relationship. |
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An item in an instance whose element is an alias concept. |
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Arcs relate concepts to each other by associating their locators. Arcs also associate concepts with resources by connecting the concept locators to the resources themselves. Arcs are also used to connect fact locators to footnote resources in footnote extended links. Arcs have a set of attributes that document the nature of the relationships expressed in extended links. Importantly all arcs have an xlink:arcrole attribute that determines the semantics of the relationship they describe. |
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Context-equal: Items or sets or sequences of items having the same item type in s-equal contexts. For a formal definition, see Section 4.10 below. |
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ancestor, child, descendant, grandparent, parent, sibling, uncle |
Relationships among elements in an XBRL instance: using the terminology of [XPATH], for any element E, another element F is its:
· ancestor if and only if F appears on the ancestor axis of E · child if and only if F appears on the child axis of E · descendant if and only if F appears on the descendant axis of E · grandparent if and only if F is the parent of the parent of E · parent if and only if F appears on the parent axis of E · sibling if and only if F appears on the child axis of the parent of E and is not E itself · uncle if and only if F is a sibling of the parent of E
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Concepts are defined in two equivalent ways. In a syntactic sense, a concept is an XML Schema element definition, defining the element to be in the item element substitution group or in the tuple element substitution group. At a semantic level, a concept is a definition of kind of fact that can be reported about the activities or nature of a business activity. |
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An element for which the attribute abstract in its XML schema declaration has the value "false" and which, therefore, may appear in an XML instance. |
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Contexts are elements that occur as children of the root element in XBRL instances. They document the entity, the period and the scenario that collectively give the appropriate context for understanding the values of items. |
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A DTS is a collection of taxonomy schemas and linkbases. The bounds of a DTS are such that the DTS includes all taxonomy schemas and linkbases that can be discovered by following links or references in the taxonomy schemas and linkbases included in the DTS. At least one taxonomy schema in a DTS must import the xbrl-instance-2003-12-31.xsd schema. See Section 3 for details on the discovery process. |
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Two items of the same concept in the same context under the same parent. For a formal definition see duplicate item in section 4.10. |
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Two occurrences of a tuple with all their descendants having the same content; more precisely: tuples that are p-equal, all of whose tuple children have a duplicate (except for being p-equal) in the other tuple, and all of whose item children have a duplicate (except for being p-equal) in the other tuple. For a formal definition see duplicate tuple in section 4.10. |
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An XML element defined using XML Schema. |
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A business entity, the subject of XBRL items. Where the [XML]/[SGML] concept of syntactic "entity" is meant, this will be pointed out. |
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The concept at the “from” end of a definition arc with arc role http://www.xbrl.org/2003/arcrole/essence‑alias. Alias and essence concepts are definitionally equivalent in the sense that valid values for an alias concept are always valid values for essence concepts to which they are related by an essence-alias relationship. |
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An item in an instance whose element is an essence concept. |
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An extended link is an element identified as an extended link using the syntax defined in the XML Linking Language [XLINK]. Extended links represent a set of relationships between information that they contain and information contained in third party documents. See Section 3.5.2.4 for more details.
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Facts can be simple, in which case their values must be expressed as simple content (except in the case of simple facts whose values are expressed as a ratio), and facts can be compound, in which case their value is made up from other simple and/or compound facts. Simple facts are expressed using items (and are referred to as items in this specification) and compound facts are expressed using tuples (and are referred to as tuples in this specification). |
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The namespace used for XBRL 2.1 instances, http://www.xbrl.org/2003/instance |
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An item is an element in the substitution group for the XBRL item element. It contains the value of the simple fact and a reference to the context (and unit for numeric items) needed to correctly interpret that fact. When items occur as children of a tuple, they must also be interpreted in light of the other items and tuples that are children of the same tuple. There are numeric items and non-numeric items, with numeric items being required to document their measurement accuracy and units of measurement. |
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In an instance, the element that is an ancestor of two elements and has no child that also appears on the ancestor axis [XPATH] of those same two elements. |
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A linkbase is a collection of XML Linking Language [XLINK] extended links that document the semantics of concepts in a taxonomy. |
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The namespace of XBRL 2.1 linkbases, http://www.xbrl.org/2003/linkbase |
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Locators supply an XPointer [XPTR] reference to the taxonomy schema element definitions that uniquely identify each concept. They provide an anchor for extended link arcs. See Section 3.5.3.7 for more details. |
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must, must not, required, shall, shall not, should, should not, may, optional |
See [RFC2119] for definitions of these and other terms as used in this specification. These include:
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An item that is not a numeric item as defined below. Dates, in particular, are not numeric. |
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An item whose simple content is derived by restriction from the XML Schema primitive types decimal, float or double, or complex content derived by restriction from the XBRL defined type fractionItemType (See Section 5.1.1.3 for details on item types). |
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An instant or duration of time. In business reporting, financial numbers and other facts are reported “as of” an instant or for a period of certain duration. Facts about instants and durations are both common. |
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Parent-equal: instance items or tuples having the same parent. For a formal definition, see Section 4.10 below. |
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Resources are XML fragments, contained within extended links that provide additional information about concepts or items. See Section 3.5.3.8 for details. |
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The root of an XBRL instance is the xbrl element. In principle, it is possible to embed an XBRL instance in any XML document. In this case, the xbrl element is the container for the XBRL instance. |
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Structure-equal: XML nodes that are either equal in the XML value space, or whose XBRL-relevant sub-elements and attributes are s-equal. For a formal definition, see Section 4.10 below. |
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A taxonomy is an XML schema and the set of XBRL linkbases that it references using linkbaseRef elements and the linkbases that are nested within it. |
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A taxonomy schema is an XML Schema [SCHEMA‑1]. A large part of many taxonomy schemas is given over to the definition of the syntax for the concepts in that taxonomy. Sections 3.1, 5 and 5.1 address this in more detail. |
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A tuple is an element in the substitution group for the XBRL tuple element. Tuples are used to bind together the parts of a compound fact. Those constituent parts are themselves, facts but they must be interpreted in light of each-other. For example, the name, age and compensation of a director of a company need to be grouped together to be correctly understood. |
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Units are XML fragments that occur as children of the root element in XBRL instances. They document the unit of measure for numeric items. Each unit element is only capable of documenting a single unit of measurement. |
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u-equal |
Unit-equal. u-equal numeric items having the same units of measurement. For a formal definition, see Section 4.10 below. |
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Value-equal: c-equal items having either the same non-numeric value, or numeric values that are equal within some tolerance defined by the lesser of their respective precision, implied precision or decimals attributes. For a formal definition see Section 4.10 below. |
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XBRL instances are XML fragments with root element, xbrl. XBRL instances contain business report facts, with each fact corresponding to a concept defined in their supporting DTS. XBRL instances also contain contexts and units that provide additional information needed to interpret the facts in the instance. |
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[XPATH]-equal: The XPath "=" operator returns the value true. For a formal definition, see Section 4.10 below. |
This specification describes two levels of conformance for XBRL aware processors. The first is required of all XBRL processors. Support for the other level of conformance will depend on the purpose of the processor.
Minimally conforming XBRL processors MUST completely and correctly implement all of the syntactic restrictions embodied in this specification.
Fully conforming XBRL processors MUST be minimally conforming and, in addition, they MUST completely and correctly implement all of the semantic restrictions relating to linkbases and XBRL instances.
All restrictions embodied in this specification apply to minimally conforming processors unless otherwise stated.
This specification uses a number of namespace prefixes when describing elements and attributes. The namespace prefix convention used is as follows:
link http://www.xbrl.org/2003/linkbase
xbrli http://www.xbrl.org/2003/instance
xl http://www.xbrl.org/2003/XLink
xlink http://www.w3.org/1999/xlink
xml http://www.w3.org/XML/1998/namespace
xsi http://www.w3.org/2001/XMLSchema-instance
Note that the xml prefix is reserved as defined in [NAMESPACES]; specifically at http://www.w3.org/TR/REC-xml-names/#nsc-NSDeclared.
Some elements and attributes defined in this specification are described without use of a namespace prefix or namespace. The normative namespaces for all elements and attributes defined in this spec are determined by the normative schemas contained herein (Appendix A).
Changes from the previous, December 2001 version of [XBRL] (and the interim 2.0a “patch” release in November 2002) were driven by two factors. Several implementations of XML Schema required the removal of an ambiguous content model from the definition of contexts. This was done without changing the language recognised by the schema. Further implementation experience within the XBRL community, including the publication of the XBRL General Ledger taxonomy, motivated many other changes. A number of business requirements documented by the XBRL International Domain working group have been incorporated.
The group element has been eliminated. It has been replaced with the xbrl element, which acts as the root element of an XBRL instance.
The set of taxonomy schemas and linkbases supporting an XBRL instance has been formally defined (as a Discoverable Taxonomy Set (DTS)). XBRL instances now identify their supporting DTS using a new schemaRef element, which points to supporting taxonomy schemas and using the existing linkbaseRef element, which points to supporting linkbases. The XML Schema Instance schemaLocation attribute is no longer required in the DTS discovery process.
The schemaRef elements must now appear first in an XBRL instance. The linkbaseRef elements must appear after the schemaRef elements and before all other elements in an XBRL instance.
Guidance has been included on the entry of numerical quantities in XBRL instances for the common case of elements from accounting related taxonomies (elements using the optional “balance” attribute in their definition). The duration element has been eliminated from context periods so durations now have to be represented using startDate and endDate. There is also additional guidance on entering data to define a period of time.
The content of the unit element has been simplified to facilitate more straightforward detection of equivalent units of measurement.
The precision attribute on numericContext has been eliminated in favour of more detailed documentation at the level of the numeric items. The CWA attribute on the numericContext element has been eliminated. The unit element has been separated from the numericContext element to enable numeric and non-numeric items to use the same context structures. The numericContext element and the nonNumericContext element have been replaced with a context element that documents only entity, period and scenario.
An additional mechanism has been introduced to enable XBRL instance preparers to make statements about the numerical accuracy of the facts reported. Specifically, a new decimals attribute has been allowed on items of numeric type to provide an alternative way to document accuracy in terms of the number of decimal places to which a numerical fact is accurate. Rules for handling precision and decimals attributes have been provided.
To specify that numbers are stated exactly in an XBRL instance, two new types have been defined for use by the decimals and precision attributes. These types enable XBRL instances to specify that numbers are represented to an infinite number of significant figures or number of decimal places.
The definition of a duplicate item has been changed to include reference to the content of any tuple structures that contain the items being compared.
Some of the arc role values and role values previously suggested are now normative and additional arc role values and role values have been defined. Some of the previously suggested arc role values have been removed. A new mechanism to define custom arc role values and role values has been added. The essence-alias arc in definition extended links has superseded the element-dimension relationship in calculation extended links. The parent-child arc no longer exists in the calculation extended link and has been replaced by summation-item arc. The parent-child arc no longer exists in the definition extended link and has been replaced by the general-special arc and by the XML Schema approach to content modelling for tuples. Because the parent-child arc in definition extended links has two possible replacements, this is one area where complete backward compatibility with 2.0 has not been achieved. Some manual intervention may be required when converting these relationships expressed in 2.0 taxonomies to 2.1. Some networks of relationships are no longer allowed to contain directed or undirected cycles.
Tuples may now have a complex content model, but MUST only use a restricted set of XML Schema constructs to describe this content model. Tuple content model definitions MUST NOT permit descendant elements for the tuple that are not in the item substitution group or in the tuple substitution group. This implies that the declarations of the descendant elements for tuples MUST be references to globally declared elements [SCHEMA‑1].
Calculations have been constrained to apply only within the scope of a tuple for items within a tuple.
The number of available item types has been expanded to include all of the appropriate built-in data types of XML Schema [SCHEMA-2].
A new type for items has been defined to allow the specification of facts that are reported as fractions (such as 22.5/77.5). The fraction type is not among the built-in data types of XML Schema [SCHEMA-2]. Since fractions have two parts, denominator and numerator, it has complex content.
Derivation of new item and tuple types from those defined by XBRL itself has been limited so that item types MUST be defined by restriction from the set of item types provided by XBRL. This set contains item types that are derived by extension from all the appropriate built-in simple types of XML Schema and a special purpose type with complex content, the fractionItemType.
The suggested xlink:role attribute on extended link locators, that indicated the root element of a relationship hierarchy, has been eliminated.
Clarity has been provided around the possibility for linkbases to be contained in taxonomy schemas.
A mandatory periodType attribute has been added to concept definitions to constrain the type of period that can be attached to items based on concepts.
XBRL defines a syntax in which a fact can be reported as the value of a well defined reporting concept within a particular context. The syntax enables software to efficiently and reliably find, extract and interpret those facts. The XBRL framework splits business reporting information into two components: XBRL instances and taxonomies.
XBRL instances contain the facts being reported while the taxonomies define the concepts being communicated by the facts. The combination of an XBRL instance and its supporting taxonomies, and additional linkbases constitute an XBRL business report.
A taxonomy is comprised of an XML Schema [SCHEMA‑1] and all of the linkbases contained in that schema or directly referenced by that schema. The XML schema is known as a taxonomy schema.
In XBRL terminology, a concept is a definition of a reporting term. Concepts manifest as XML Schema [SCHEMA‑1] element definitions. In the taxonomy schema a concept is given a concrete name and a type. The type defines the kind of data types allowed for facts measured according to the concept definition. For example, a “cash” concept would typically have a monetary type. This declares that when cash is reported, its value will be monetary. In contrast, a “accountingPoliciesNote” concept would typically have a string type so that, when the “accountingPoliciesNote” is reported in an XBRL instance, its value would be interpreted as a string of characters. Additional constraints on how concepts can be used are documented by additional XBRL attributes on the XML Schema [SCHEMA‑1] element definitions that correspond to the concepts. See Section 5.1.1 for details.
The linkbases in a taxonomy further document the meaning of the concepts by expressing relationships between concepts (inter-concept relationships) and by relating concepts to their documentation. See Section 5.2 for details.
A linkbase is a collection of extended links. There are five different kinds of extended links used in taxonomies to document concepts: definition, calculation, presentation, label and reference. The first three types of extended link express inter-concept relationships, and the last two express relationships between concept and their documentation.
The linkbases MAY be contained in a separate document from the taxonomy schema, and they MAY be embedded in the taxonomy schema. When a linkbase is not embedded in a taxonomy schema, the taxonomy schema MUST contain a linkbaseRef to point to the linkbase document if the linkbase is to be part of the taxonomy built around the taxonomy schema.
While a taxonomy defines reporting concepts, it does not contain the actual values of facts based on the defined concepts. The fact values are contained in XBRL instances and are referred to as “facts”. Besides the actual value of a fact, such as “cash is 500,000”, the XBRL instance provides contextual information necessary for interpreting the fact values. For numeric facts, the XBRL instance also documents measurement accuracy and measurement units.
An XBRL instance can be supported by more than one taxonomy. Also, taxonomies can be interconnected, extending and modifying each other in various ways. Generally, it is necessary to consider multiple related taxonomies together when interpreting an XBRL instance. The set of related taxonomies is called a Discoverable Taxonomy Set (DTS). A DTS is a collection of taxonomy schemas and linkbases. The bounds of a DTS are determined by starting from some set of documents (instance, taxonomy schema, or linkbase) and following DTS discovery rules. Although an XBRL instance can be the starting point for DTS discovery, the XBRL instance itself is not part of the DTS. Taxonomy schemas and linkbases that are used as starting points for DTS discovery are part of the DTS that they discover.
DTS rules of discovery:
Taxonomy schemas in the DTS are those:
1. referenced directly from an XBRL instance using the schemaRef, roleRef or arcroleRef element. The xlink:href attribute on the schemaRef, roleRef or arcroleRef element contains the URL of the taxonomy schema that is discovered. Every taxonomy schema that is referenced by the schemaRef, roleRef or arcroleRef element MUST be discovered.
2. referenced from a discovered taxonomy schema via an XML Schema import or include element. Every taxonomy schema that is referenced by an import or include element in a discovered taxonomy schema MUST be discovered.
NOTE: since <redefine> is prohibited in taxonomy schemas it cannot play a role in DTS discovery.
3. referenced from a discovered linkbase document via a loc element. Every taxonomy schema that is referenced by an xlink:href attribute on a loc element in a discovered linkbase MUST be discovered.
4. referenced from a discovered linkbase document via a roleRef element. Every taxonomy schema that is referenced by an xlink:href attribute on a roleRef element in a discovered linkbase MUST be discovered.
5. referenced from a discovered linkbase document via an arcroleRef element. Every taxonomy schema that is referenced by an xlink:href attribute on an arcroleRef element in a discovered linkbase MUST be discovered.
Linkbase documents in the DTS are those:
1. referenced directly from an XBRL instance via the linkbaseRef element. The xlink:href attribute contains the URL of the linkbase document being discovered. Every linkbase that is referenced by the linkbaseRef element MUST be discovered.
2. referenced from a discovered taxonomy schema via the linkbaseRef element. The xlink:href attribute contains the URL of the linkbase being discovered. Every linkbase that is referenced by the linkbaseRef element MUST be discovered.
3. that occur at the XPath "schema/annotation/appinfo/*" in a discovered taxonomy schema (Throughout this specification, schema, annotation and appinfo are all elements defined in the XML Schema namespace).
4. referenced from a discovered linkbase document via a loc element. Every linkbase that contains a resource that is referenced by an xlink:href attribute on a loc element in a discovered linkbase MUST be discovered.
For example, the “Financial Reporting for Commercial and Industrial Companies, US GAAP DTS” consists of well-defined concepts within the US Generally Accepted Accounting Principles (GAAP) when those principles are applied to Commercial and Industrial (C&I) companies. This DTS contains an “expense” concept.
A hospital XBRL instance may use these concepts from the US GAAP C&I DTS as well as an additional concept “physician salaries” that is defined in a separate taxonomy. This taxonomy would include linkbases that relate the “physician salaries” concept to the “expense” concept in the US GAAP C&I DTS. The hospital XBRL instance would have a schemaRef element pointing to the hospital taxonomy. This XBRL instance would be the starting place for determining the DTS that supports the XBRL instance. The discovery starts by following the schemaRef element to the hospital taxonomy. In the hospital taxonomy there would be a linkbaseRef element pointing to its linkbases. One of the linkbases contains a loc element pointing to the “expense” concept in one the US GAAP C&I taxonomies. The taxonomy that contains the “expense” concept would point to the other taxonomies in the US GAAP C&I DTS. Following this discovery process, all necessary taxonomies would be discovered and the result would be a DTS that includes the US GAAP C&I DTS and the hospital specific taxonomy.
As this example shows, DTSs can also be used as “building blocks” to create larger, more sophisticated DTSs. Users MAY compose groups of existing DTSs into higher-level DTSs and MAY selectively add concepts and concept relationships via extension taxonomies.
While some consuming applications might be able to perform processing on an XBRL data file without referring to a DTS, normally, the interpretation and processing of any given XBRL fact is relative to the contents of a DTS.
For example, given an XBRL instance, to correctly produce a list of facts with the entries in the list corresponding to an ordered set of concepts, it is necessary to find the label corresponding to each fact being listed. The labels are contained in label extended links. The locations of the label extended links may be specified by linkbaseRef elements in the taxonomy schemas that have been identified as supporting the facts being presented. The label extended link locations may also be specified by linkbaseRef elements in the XBRL instance itself.
When processing an XBRL instance, consuming applications MUST use all of the linkbases referenced directly or indirectly in this way, if they are relevant to the processing activities. All references to taxonomy schemas and linkbases MUST be resolved when determining the DTS supporting an XBRL instance.
There are many applications that require business information to be transmitted securely, with a particular emphasis on data integrity (leading to the use of hash totals, etc.) and with confidentiality (leading to the use of cryptographic means of protection). XBRL deliberately provides neither of these mechanisms, since its focus is on transmission of actual content in an agreed-upon format. it is assumed that, like any other block of data, data integrity can be enhanced by adding redundant error correction bytes, by cryptographic hashing and signing with a private key, etc. These mechanisms are all outside the scope of XBRL.
An XBRL instance does not have to be aware of whether all or some of it has been manipulated to be signed, encrypted, canonicalised, compressed, etc. By the time XBRL processing has to take place, all of those manipulations will have been unwound, and the XBRL payload will be free of any evidence of those operations.
XBRL instances, XBRL linkbases and XBRL taxonomy schemas MUST comply with the syntax requirements imposed in this specification. Many of these syntax requirements are expressed using XML Schemas so a part of the validation process can be performed using XML Schema validation software. Some of these syntax requirements are not or cannot be expressed using XML Schemas and so, MUST be handled using other validation technologies.
Consuming applications MAY also check that the data in an XBRL instance is consistent with the semantics expressed in the DTS supporting the instance. Semantic inconsistencies do not invalidate the XBRL instances in which they occur. However, this specification identifies the semantic inconsistencies that can be tested for by fully conformant XBRL processors.
Links between XML fragments occur in many forms in XBRL. There are links between XBRL instances and their supporting DTS. There are links between XBRL instance facts and the footnotes that describe relationships between those facts. There are links between concept syntax definitions and their semantics, defined in linkbases. The semantics themselves are expressed in the networks of links that constitute the linkbases. XBRL expresses all of these links using the syntax defined in the XLink specification [XLINK]. XBRL uses both the simple links and the extended links defined in the [XLINK] specification.
The [XLINK] specification establishes the syntax and semantics for a set of attributes in the [XLINK] namespace, http://www.w3.org/1999/xlink. These attributes can then be used on elements defined in another namespace to document various kinds of links between XML fragments. Many of these attributes are used extensively in XBRL. Others have no semantics that are relevant to the links defined by XBRL. These other attributes are permitted by the XML Schema syntax constraints but they are not documented or given any specific semantics in this specification. Examples include the xlink:show and the xlink:actuate attributes.
This section documents the generic forms of the simple links and the extended links used in XBRL. Specific elements that use the simple link or extended link syntax are documented in detail in the relevant sections of this specification dealing with the syntax of XBRL instances or the syntax of XBRL taxonomies.
The syntax of the generic [XLINK] structures used by XBRL is constrained by two XML Schemas: the xlink-2003-12-31.xsd (normative) that defines the syntax for the [XLINK] attributes; and the xl-2003-12-31.xsd (normative) that defines the content models for the various kinds of link-related elements defined by this specification.
A simple link is a link that points from one resource to another [XLINK] http://www.w3.org/TR/xlink/#simple-links. Some examples of how XBRL uses simple links are:
· to point to linkbases from XBRL instances and from taxonomy schemas (See Section 4.2.5)
· to point to taxonomy schemas from XBRL instances (See Section 4.2).
The XML Schema constraints on the simple links used by XBRL are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="simpleType"> <annotation> <documentation> Type for the simple links defined in XBRL </documentation> </annotation> <complexContent> <restriction base="anyType"> <attributeGroup ref="xlink:simpleType"/> <attribute ref="xlink:href" use="required" /> <attribute ref="xlink:arcrole" use="optional" /> <attribute ref="xlink:role" use="optional" /> <attribute ref="xlink:title" use="optional" /> <attribute ref="xlink:show" use="optional" /> <attribute ref="xlink:actuate" use="optional" /> <anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax" /> </restriction> </complexContent> </complexType> <element name="simple" type="xl:simpleType" abstract="true"> <annotation> <documentation> The abstract element at the head of the simple link substitution group. </documentation> </annotation> </element>
</schema> |
The xlink:type attribute MUST occur and MUST have the fixed content “simple”.
A simple link MUST have an xlink:href attribute. The xlink:href attribute MUST be a URI. The URI MUST point to an XML document or to an XML fragment within an XML document. If the URI is relative, it MUST be resolved to obtain an absolute URI as specified in XML Base specification [XML Base]. For details on the allowable forms of XPointer [XPTR] syntax in the URI see section 3.5.4
The optional xlink:role attribute MUST take URI values. If it is provided, the xlink:role attribute MUST NOT be empty.
If it occurs, the xlink:arcrole attribute MUST NOT be an empty string.
The xml:base attribute [XML Base] MAY appear on the simple links, participating in the resolution of relative URIs specified in their xlink:href attributes.
The [XLINK] specification defines linkbases in the following way: “documents containing collections of inbound and third-party links are called link databases, or linkbases” [XLINK] (http://www.w3.org/TR/2001/REC-xlink-20010627/#dt-linkbase). While the syntax for concepts is defined in taxonomy schemas, the semantics of those concepts are defined in XBRL linkbases. Linkbases are extended links or they are elements that contain extended links. Linkbases MAY also contain documentation elements.
The linkbase element is intended to be used as a linkbase container. The XML Schema constraints on the linkbase element are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="linkbase"> <annotation> <documentation> Definition of the linkbase element. Used to contain a set of zero or more extended link elements. </documentation> </annotation> <complexType> <choice minOccurs="0" maxOccurs="unbounded"> <element ref="link:documentation"/> <element ref="link:roleRef"/> <element ref="link:arcroleRef"/> <element ref="xl:extended"/> </choice> <attribute name="id" type="ID" use="optional"/> <anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax" /> </complexType> </element>
</schema> |
Example 1. A skeletal linkbase
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<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:samp="http://www.xbrl.org/sample" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/sample samp001.xsd" xml:base="http://www.xbrl.org/sample">
<calculationLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended"> <!-- ... --> </calculationLink>
</linkbase> |
|
Meaning: Use of linkbase as the root element, holding namespace prefix definitions and the schemaLocation attribute. The “xml:” prefix need not be declared. One extended link element, the calculationLink, is contained in the linkbase. |
The linkbase element MAY have an id attribute. The value of the id attribute MUST conform to the [XML] rules for attributes with the ID type (http://www.w3.org/TR/REC-xml#NT-TokenizedType).
The xml:base attribute [XML Base] MAY appear on the linkbase element, participating in the resolution of relative URIs in the contained extended links.
All linkbase elements MAY also contain documentation elements.
The XML Schema constraints on the documentation element are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="documentationType"> <annotation> <documentation> Element type to use for documentation of extended links and linkbases. </documentation> </annotation> <simpleContent> <extension base="string"> <anyAttribute namespace="##other" processContents="lax"/> </extension> </simpleContent> </complexType>
<element name="documentation" type="xl:documentationType" abstract="true"> <annotation> <documentation> Abstract element to use for documentation of extended links and linkbases. </documentation> </annotation> </element>
</schema>
<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="documentation" type="xl:documentationType" substitutionGroup="xl:documentation"> <annotation> <documentation> Concrete element to use for documentation of extended links and linkbases. </documentation> </annotation> </element>
</schema> |
The documentation element MUST have string content. The documentation element MAY contain any attribute that is not defined in the XBRL linkbase namespace, http://www.xbrl.org/2003/linkbase. For example, the documentation element MAY use the xml:lang attribute to indicate the language used for the documentation.
The roleRef element is used to resolve custom xlink:role values that are used in a linkbase or XBRL instance (for footnoteLink and footnote). The roleRef element is a simple link, as defined in Section 3.5.1. The roleRef element points to the roleType element in a taxonomy schema document that declares the xlink:role attribute value (see section 5.1.3). All custom xlink:role attribute values used in a linkbase or XBRL instance on definitionLink, calculationLink, presentationLink, labelLink, referenceLink, footnoteLink, label, reference and footnote elements MUST be resolvable via a roleRef element. The roleRef element MUST apply only to xlink:role attribute values where the xlink:role attribute has an ancestor that is the parent element of the roleRef element.
During DTS discovery, the taxonomy schema that is pointed to by the roleRef element is discovered.
The XML Schema constraints on the roleRef element are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="roleRef" substitutionGroup="xl:simple"> <annotation> <documentation> Definition of the roleRef element - used to link to resolve xlink:role attribute values to the roleType element declaration. </documentation> </annotation> <complexType> <complexContent> <extension base="xl:simpleType"> <attribute name="roleURI" type="xlink:nonEmptyURI" use="required"> <annotation> <documentation> This attribute contains the role name. </documentation> </annotation> </attribute> </extension> </complexContent> </complexType> </element>
</schema> |
The xlink:type attribute MUST occur and MUST have the fixed content “simple”.
A roleRef element MUST have an xlink:href attribute. The xlink:href attribute MUST be a URI. The URI MUST point to a roleType element in a taxonomy schema document. If the URI reference is relative, its absolute version MUST be determined as specified in [XML Base] before use. For details on the allowable forms of XPointer [XPTR] syntax in the URI see section 3.5.4.
The xlink:arcrole attribute MAY be used on the roleRef element. No semantics are defined for the xlink:arcrole attribute when it occurs on the roleRef element.
The optional xlink:role attribute MUST take URI values. If it is provided, the xlink:role attribute MUST NOT be empty. No semantics are defined for the xlink:role attribute when it occurs on the roleRef element.
The roleURI attribute MUST occur on the roleRef element. The roleURI attribute identifies the xlink:role attribute value that is defined by the XML resource that is pointed to by the roleRef element. The value of this attribute MUST match the value of the roleURI attribute on the roleType element that the roleRef element is pointing to. Within a linkbase or an XBRL instance there MUST NOT be more than one roleRef element with the same roleURI attribute value.
The arcroleRef element is used to resolve custom xlink:arcrole values that are used in a linkbase or an XBRL instance (for footnoteArc). The arcroleRef element is a simple link, as defined in Section 3.5.1. The arcroleRef element points to the arcroleType element in a taxonomy schema document that declares the xlink:arcrole attribute value (see section 5.1.4). All custom xlink:arcrole attribute values used in a linkbase or an XBRL instance on a definitionArc, calculationArc, presentationArc, labelArc, referenceArc or footnoteArc MUST be resolvable via an arcroleRef element. The arcroleRef element MUST apply only to xlink:arcrole attribute values where the xlink:arcrole attribute has an ancestor that is the parent element of the arcroleRef element.
During DTS discovery, the taxonomy schema that is pointed to by the arcroleRef element is discovered.
The XML Schema definition of the arcroleRef element is shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="arcroleRef" substitutionGroup="xl:simple"> <annotation> <documentation> Definition of the roleRef element - used to link to resolve xlink:arcrole attribute values to the arcroleType element declaration. </documentation> </annotation> <complexType> <complexContent> <extension base="xl:simpleType"> <attribute name="arcroleURI" type="xlink:nonEmptyURI" use="required"> <annotation> <documentation> This attribute contains the arc role name. </documentation> </annotation> </attribute> </extension> </complexContent> </complexType> </element>
</schema> |
The xlink:type attribute MUST occur and MUST have the fixed content “simple”.
An arcroleRef element MUST have an xlink:href attribute. The xlink:href attribute MUST be a URI. The URI MUST point to an arcroleType element in a taxonomy schema document. If the URI reference is relative, its absolute version MUST be determined as specified in [XML Base] before use. For details on the allowable forms of XPointer [XPTR] syntax in the URI see section 3.5.4.
The xlink:arcrole attribute MAY be used on the arcroleRef element. No semantics are defined for the xlink:arcrole attribute when it occurs on the arcroleRef element.
The optional xlink:role attribute MUST take URI values. If it is provided, the xlink:role attribute MUST NOT be empty. No semantics are defined for the xlink:role attribute when it occurs on the arcroleRef element.
The arcroleURI attribute MUST occur on the arcroleRef element. The arcroleURI attribute identifies the xlink:arcrole attribute value that is defined by the XML resource that is pointed to by the arcroleRef element. The value of this attribute MUST match the value of the arcroleURI attribute on the arcroleType element that the arcroleRef element is pointing to. Within a linkbase or an XBRL instance there MUST NOT be more than one arcroleRef element with the same arcroleURI attribute value.
Extended links are [XLINK] annotated XML fragments that document a set of relationships between resources. XBRL extended links document relationships between resources that are XML fragments.
The generic XML Schema constraints on the extended links used by XBRL are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="extendedType"> <annotation> <documentation> Generic extended link type </documentation> </annotation> <complexContent> <restriction base="anyType"> <choice minOccurs="0" maxOccurs="unbounded"> <element ref="xl:title" /> <element ref="xl:documentation" /> <element ref="xl:locator" /> <element ref="xl:arc" /> <element ref="xl:resource" /> </choice> <attributeGroup ref="xlink:extendedType"/> <attribute ref="xlink:role" use="required" /> <attribute ref="xlink:title" use="optional" /> <attribute name="id" type="ID" use="optional" /> <anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax" /> </restriction> </complexContent> </complexType> <element name="extended" type="xl:extendedType" abstract="true"> <annotation> <documentation> Abstract extended link element at head of extended link substitution group. </documentation> </annotation> </element>
</schema> |
XBRL extended links MAY contain five different types of child elements:
· documentation elements;
· title elements (titles);
· locator elements (locators);
· resource elements (resources); and
· arc elements (arcs).
The documentation element is for XBRL documentation purposes only and has no [XLINK]-specific semantics. Titles, locators, resources and arcs are identified by specific [XLINK] attributes. If the titles, locators, resources and arcs are not direct children of an extended element, then they have no [XLINK] specified meaning, and hence have no XBRL-specified meaning.
The attributes for XBRL extended links are described below.
Extended links MAY have an id attribute. The value of the id attribute MUST conform to the [XML] rules for attributes with the ID type (See http://www.w3.org/TR/REC-xml#NT-TokenizedType for details). The id attribute identifies an extended link (see Section 4.8) so that it may be referenced directly by simple links.
The xlink:type attribute MUST occur on extended links and MUST have the fixed content “extended”.
The xlink:role attribute MUST occur on extended links defined in this specification. The content of the xlink:role attribute is referred to as the extended link role value. The extended link role value MUST be used by applications to partition extended links into separate networks of relationships. See Section 5.2 for details on how the semantics embodied in extended link arcs is contingent on extended link arc role values. The xlink:role attribute MUST NOT be empty. The xlink:role attribute value MUST be a URI value as defined by the [XLINK] specification. A standard value that MAY be used for extended link xlink:role attributes, without requiring a custom role type definition (See Section 5.1.3), is:
http://www.xbrl.org/2003/role/link
For the extended link elements defined in this specification (definitionLink, calculationLink, presentationLink, labelLink, referenceLink and footnoteLink), all other xlink:role values MUST be defined with a custom role type definition roleType element (See Section 5.1.3) and resolved via a roleRef element (see Section 3.5.2.4).
The xml:base attribute [XML Base] MAY appear on the extended links, participating in the resolution of relative URIs that they contain.
All XBRL extended links MAY contain documentation elements.
The documentation elements in extended links conform to the same syntax requirements that apply to documentation elements in linkbase elements. See Section 3.5.2.1 for details.
All XBRL extended links MAY contain titles. Titles may be used to document extended links, as an alternative to the more limited xlink:title attributes. They are particularly useful where information needs to be provided in multiple languages. Titles have no XBRL specified semantics. To use a title in an extended link, it is necessary to define a new element that is in the substitution group for the abstract title element.
The XML Schema constraints on the titles are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="titleType"> <annotation> <documentation> Type for the abstract title element - used as a title element template. </documentation> </annotation> <complexContent> <restriction base="anyType"> <attributeGroup ref="xlink:titleType"/> </restriction> </complexContent> </complexType> <element name="title" type="xl:titleType" abstract="true"> <annotation> <documentation> Generic title element for use in extended link documentation. Used on extended links, arcs, locators. See http://www.w3.org/TR/xlink/#title-element for details. </documentation> </annotation> </element>
</schema> |
The xlink:type attribute MUST occur on all titles and MUST have the fixed content “title”.
Locators are child elements of an extended link that point to resources external to the extended link itself. All XBRL extended links MAY contain locators.
The XML Schema constraints on generic locators are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="locatorType"> <annotation> <documentation> Generic locator type. </documentation> </annotation> <complexContent> <restriction base="anyType"> <sequence> <element ref="xl:title" minOccurs="0" maxOccurs="unbounded" /> </sequence> <attributeGroup ref="xlink:locatorType"/> <attribute ref="xlink:href" use="required" /> <attribute ref="xlink:label" use="required" /> <attribute ref="xlink:role" use="optional" /> <attribute ref="xlink:title" use="optional" /> </restriction> </complexContent> </complexType> <element name="locator" type="xl:locatorType" abstract="true"> <annotation> <documentation> Abstract locator element to be used as head of locator substitution group for all extended link locators in XBRL. </documentation> </annotation> </element>
</schema> |
For consistency, the loc element is the only locator defined for use in XBRL extended links. The loc element is a concrete version of the generic locator. The XML Schema syntax constraints on the loc element are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="loc" type="xl:locatorType" substitutionGroup="xl:locator"> <annotation> <documentation> Concrete locator element. The loc element is the XLink locator element for all extended links in XBRL. </documentation> </annotation> </element>
</schema> |
The xlink:type attribute MUST occur on all locators and MUST have the fixed content “locator”.
A locator MUST have an xlink:href attribute. The xlink:href attribute MUST be a URI. The URI MUST point to an XML document or to one or more XML fragments within an XML document. If the URI is relative, it MUST be resolved to obtain an absolute URI as specified in XML Base specification [XML Base]. For details on the allowable forms of XPointer [XPTR] syntax in the URI see section 3.5.4.
The xlink:label attribute on a locator identifies the locator so that arcs in the same extended link can reference it. Multiple locators and resources in an extended link MAY have the same xlink:label attribute value. The xlink:label attribute value MUST be an NCName [XML] (http://www.w3.org/TR/REC-xml-names/#NT-NCName). This requirement means that xlink:label attributes MUST begin with a letter or an underscore.
Locators MAY contain titles. Title children of locators MUST conform to the same restrictions applying to title children of extended links. See Section 3.5.3.6 for details.
Some XBRL extended links MAY contain resources. A resource is an XML fragment in an extended link that is related to other resources in the extended link and to resources outside of the extended link.
The XML Schema constraints on generic resources are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="resourceType"> <annotation> <documentation> Generic type for the resource type element </documentation> </annotation> <complexContent mixed="true"> <restriction base="anyType"> <attributeGroup ref="xlink:resourceType"/> <attribute ref="xlink:label" use="required" /> <attribute ref="xlink:role" use="optional" /> <attribute ref="xlink:title" use="optional" /> <attribute name="id" type="ID" use="optional" /> </restriction> </complexContent> </complexType> <element name="resource" type="xl:resourceType" abstract="true"> <annotation> <documentation> Abstract element to use as head of resource element substitution group. </documentation> </annotation> </element>
</schema> |
The content of generic resources is very loosely constrained. More specific constraints are applied by this specification for specific kinds of resources in specific kinds of extended links.
The xlink:type attribute MUST occur on all resources and MUST have the fixed content “resource”.
The xlink:label attribute on a resource identifies the resource so that arcs in the same extended link can reference it. The xlink:label attribute on resources conforms to the same requirements applying to the xlink:label attribute on locators. See Section 3.5.3.7.3 for details. Several resources in an extended link MAY have the same label.
The optional xlink:role attribute on a resource is referred to as the resource role value.
Resources MAY contain an xlink:role attribute, which SHOULD distinguish between resources based on the nature of the information that they contain. Some of the resources defined in this specification have a set of standard resource role values defined for them. The xlink:role attribute value MUST be a URI value as defined by the [XLINK] specification. For the resource elements defined in this specification (label, reference and footnote), all xlink:role values that are not standard for the resource element MUST be defined with a custom role type definition roleType element (see Section 5.1.3) and resolved via a roleRef element (see Section 3.5.2.4). Standard xlink:role values are defined in specific section for each resource element.
The id attribute MAY occur on all resources in XBRL extended links. The value of the id attribute MUST conform to the [XML] rules for attributes with the ID type (http://www.w3.org/TR/REC-xml#NT-TokenizedType). The id attribute identifies the resource so that it may be referenced by locators in other extended links for the purposes of arc prohibition (See Section 3.5.3.9.5).
All XBRL extended links MAY contain arcs. Arcs document relationships between resources identified by locators in extended links or occurring as resources in extended links.
The XML Schema constraints on generic arcs are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<simpleType name="useEnum"> <annotation> <documentation> Enumerated values for the use attribute on extended link arcs. </documentation> </annotation> <restriction base="NMTOKEN"> <enumeration value="optional" /> <enumeration value="prohibited" /> </restriction> </simpleType>
<complexType name="arcType"> <annotation> <documentation> basic extended link arc type - extended where necessary for specific arcs Extends the generic arc type by adding use, priority and order attributes. </documentation> </annotation> <complexContent> <restriction base="anyType"> <sequence> <element ref="xl:title" minOccurs="0" maxOccurs="unbounded" /> </sequence> <attributeGroup ref="xlink:arcType"/> <attribute ref="xlink:from" use="required" /> <attribute ref="xlink:to" use="required" /> <attribute ref="xlink:arcrole" use="required" /> <attribute ref="xlink:title" use="optional" /> <attribute ref="xlink:show" use="optional" /> <attribute ref="xlink:actuate" use="optional" /> <attribute name="order" type="decimal" use="optional" /> <attribute name="use" type="xl:useEnum" use="optional" /> <attribute name="priority" type="integer" use="optional" /> <anyAttribute namespace="##other" processContents="lax" /> </restriction> </complexContent> </complexType> <element name="arc" type="xl:arcType" abstract="true"> <annotation> <documentation> Abstract element to use as head of arc element substitution group. </documentation> </annotation> </element>
</schema> |
Arcs represent relationships between the XML fragments referenced by their [XLINK] attributes: xlink:from and xlink:to. The xlink:from and the xlink:to attributes represent each side of the arc. These two attributes contain the xlink:label attribute values of locators and resources within the same extended link as the arc itself. For a locator, the referenced XML fragments comprise the set of XML elements identified by the xlink:href attribute on the locator. For a resource, the referenced XML fragment is the resource element itself.
An arc MAY reference multiple XML fragments on each side (“from” and “to”) of the arc. This can occur if there are multiple locators and/or resources in the extended link with the same xlink:label attribute value identified by the xlink:from or xlink:to attribute of the arc. Such arcs represent a set of one-to-one relationships between each of the XML fragments on their “from” side and each of the XML fragments on their “to” side.
Example 2. One-to-One arc relationships [XLINK]
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This presentation link contains an arc that relates one XBRL concept to one other XBRL concept. The XML fragment on the “from” side is the conceptA element definition, found in the example.xsd taxonomy schema. The XML fragment on the “to” side is the conceptB element definition, also found in the example.xsd taxonomy schema. <presentationLink xlink:type="extended" |
Example 3. One-to-Many arc relationships [XLINK]
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This label link contains a single arc that relates one XBRL concept to two XBRL labels. This is accomplished by giving each of the label resources the same xlink:label attribute value, which, in turn, is the same as the xlink:to attribute value on the arc. The arc represents two relationships, one between conceptA and the standard label (“Concept A”) and another between conceptA and the total label (“Total of Concept A”). <labelLink xlink:type="extended" This extended link could also express the same two relationships but be written with separate xlink:label attribute values for each label and two arcs. <labelLink xlink:type="extended" Semantically, these two extended links represent the same set of relationships between the concept and its labels. |
Example 4. Many-to-Many arc relationships [XLINK]
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This label link contains a single arc that relates two concepts to two labels. This is accomplished by each of the locators for the concepts having the same xlink:label attribute value, which in turn is the same as the xlink:from attribute value on the arc, and by each of the label resources having the same xlink:label attribute value, which in turn is the same as the xlink:to attribute value. <labelLink xlink:type="extended" The arc represents 4 relationships as follows: 1. between conceptA and the label resource “Concept A or B” 2. between conceptA and the label resource “Total of Concept A or B” 3. between conceptB and the label resource “Concept A or B” 4. between conceptB and the label resource “Total of Concept A or B” Like the one-to-many example, this extended link could be re-written as 4 one-to-one arcs, where each locator and each resource has a unique xlink:label attribute value. It could also be re-written as two one-to-two arcs where the label resources have the same xlink:label attribute value and the locators have unique xlink:label attribute values or vice versa. |
There MUST not be any [XLINK] duplicate arcs within an extended link. [XLINK] duplicate arcs are arcs that have the same pair of values for the xlink:from and xlink:to attributes within an extended link.
Example 5. Correct use of arcs according to [XLINK]
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[XLINK] forbids duplicate arcs within a single extended link and ignores arcrole in determining duplicates so the following example is invalid (See Section 5.2.6 for details of definitionLink extended links): <definitionLink xlink:type="extended" instead, an alternative construction that is legal according to [XLINK], such as the following, MUST be used: <definitionLink xlink:type="extended" |
The xlink:type attribute MUST occur on all arcs and MUST have the fixed content “arc”.
The xlink:from attribute on an arc MUST be equal to the value of an xlink:label attribute of at least one locator or resource in the same extended link element as the arc element itself.
The xlink:from attribute value MUST be an NCName [XML] (http://www.w3.org/TR/REC-xml-names/#NT-NCName). This requirement means that xlink:from attributes MUST begin with a letter or an underscore.
The xlink:to attribute on an arc MUST be equal to the value of an xlink:label attribute of at least one locator or resource in the same extended link element as the arc element itself.
The xlink:to attribute value MUST be an NCName [XML] (http://www.w3.org/TR/REC-xml-names/#NT-NCName). This requirement means that xlink:to attributes MUST begin with a letter or an underscore.
The xlink:arcrole attribute documents the specific kind of relationship being expressed by the arc. Its value is referred to as an arc role value. A set of standard arc role values are defined and given specific meaning in this specification for each arc element. These are documented in the sections describing the specific XBRL arc elements (labelArc, referenceArc, calculationArc, definitionArc, presentationArc, and footnoteArc) on which they are to be used.
Custom arc role values MAY be defined in taxonomy schemas. The semantics for custom arc role values are defined using the arcroleType element (see Section 5.1.4). An arc role value MUST be an absolute URI that can be resolved to address the fragment of an XML Schema document containing the arcroleType element.
The optional order attribute MUST have a decimal value that that indicates the order in which applications MUST display siblings when hierarchical networks of relationships are being displayed. If missing, the order attribute value MUST default to "1". If multiple siblings in the hierarchy have the same order attribute value, the presentation order of those siblings is application dependent. The value of the order attribute is not restricted to integers, which is useful when there is a need to place a new sibling in between two previously defined siblings.
Arcs MAY contain titles. Title children of arcs MUST conform to the same restrictions applying to title children of extended links. See Section 3.5.3.6 for details.
A taxonomy author will generally not have write permissions on linkbases created by other taxonomy authors. In situations where a taxonomy author needs to modify the relationships expressed in linkbases that they cannot alter directly, they may create new linkbases that contain arcs that represent relationships that prohibit or override the specific relationships that are to be modified. Both overriding and prohibiting an existing relationship is achieved by constructing a new arc.
A prohibiting arc is an arc that represents a prohibiting relationship or a set of prohibiting relationships. A prohibiting relationship is a relationship that negates another relationship. An overriding arc is an arc that represents an overriding relationship or a set of overriding relationships. An overriding relationship is a relationship that supersedes another relationship. Prohibition and overriding are relevant when determining the relationships in a network of relationships represented in a DTS (See Section 3.5.3.9.7.3).
Arcs that represent prohibiting and overriding relationships are controlled by two attributes, use and priority, which are available on all arc elements defined in this specification.
The optional use attribute MUST take one of two possible values – "optional", or "prohibited".
use="optional" indicates that the arc represents a relationship or set of relationships that MAY participate in a network of relationships represented by arcs in a DTS (See Section 3.5.3.9.7.3 for details on networks of relationships in a DTS). This is the default value that MUST be inferred for the use attribute if the use attribute is not specified.
use="prohibited" indicates that this arc represents a relationship or set of relationships that prohibit themselves and other equivalent relationships from participating in a network of relationships represented by arcs in a DTS (See Section 3.5.3.9.7.4 for details on relationship equivalency). Such relationships are referred to as prohibiting relationships.
The content of the priority attribute MUST be an integer. The default value of the priority attribute is “0”. The priority attribute is used when applying the rules of prohibition and overriding in a network of relationships. Each relationship has a priority equal to the value of the priority attribute on the arc that represents the relationship.
The arcs expressed in the extended links within a DTS describe networks of relationships between XML fragments.
Individually, each arc describes one or more relationships. However, within a DTS, only some of those relationships participate in the networks of relationships described by the DTS.
All relationships in the DTS are candidates for inclusion in the networks of relationships described by the DTS. However, some relationships are excluded from the networks of relationships described by the DTS because they are prohibited or overridden by other relationships.
All arcs in a DTS are grouped into base sets of arcs. All arcs in a base set of arcs:
· have the same local name, namespace and xlink:arcrole attribute value on the arc element; and
· are contained in extended link elements that have the same local name, namespace, and xlink:role attribute value.
Each base set of arcs in a DTS represents the set of candidates for inclusion in a network of relationships. For each base set of arcs in a DTS, the rules of relationship prohibition and overriding determine the subset of relationships in that base set that participate in the corresponding network of relationships represented by arcs in the DTS.
Applying the rules of relationship prohibition and overriding requires a comparison of each relationship represented by arcs in the base set to all other relationships represented by arcs in the base set.
Two relationships represented by arcs in a given base set are equivalent if:
· the value of any non-XLink attribute, except use and priority, on a defining arc is s-equal to the s-equal non-XLink attribute on the other arc or is s-equal to the value that the non-XLink attribute defaults to, if there is no such s-equal non-XLink attribute on the other arc (see section 4.10 for definition of s-equal); and
· the XML fragments on the “from” sides of the relationships are identical as defined in section 4.10 (See Section 3.5.3.9 for an explanation of the XML fragments identified by the xlink:from attribute on arcs); and
· the XML fragments on the “to” sides of the relationships are identical as defined in section 4.10 (See Section 3.5.3.9 for an explanation of the XML fragments identified by the xlink:to attribute on arcs).
The rules of prohibiting and overriding relationships employ the use and priority attributes on arcs and the notion of relationship equivalence to determine, for each relationship expressed by arcs in a base set, if that relationship is included in the network of relationships for that base set of arcs.
The rules of prohibition and overriding are applied to each set of equivalent relationships represented by arcs in the base set as follows:
i. None of the prohibiting relationships in the set are ever included in the network of relationships represented by arcs in the base set.
ii. If only one relationship has the highest priority and that relationship is not prohibiting, then that relationship is an overriding relationship and is included in the network of relationships for the base set. All other equivalent relationships are not included in the network of relationships for the base set of arcs.
iii. If there is more than one relationship with the highest priority and none of them are prohibiting, then one of those highest priority relationships MUST be included in the network of relationships for the base set of arcs. The relationship that is chosen for inclusion is an overriding relationship. All of the other equivalent relationships MUST be excluded from the network of relationships (these are overridden relationships) for the base set of arcs. The choice of which relationship is included in the network of relationships for the base set of arcs is application dependent.
iv. If there are one or more relationships with the highest priority and at least one of those relationships is prohibiting, then none of the equivalent relationships are included in the network of relationships (these equivalent relationships, which are not prohibiting relationships, are prohibited relationships) for the base set of arcs.
Example 6. Prohibiting and overriding relationships
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The following set of examples includes some unlikely but nevertheless possible situations and demonstrates how they are dealt with according to the rules of prohibiting and overriding relationships. These examples anticipate a series of extension taxonomies being created, possibly by different authors who do not have write access to the taxonomies that they are extending. |
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If the following two arcs in a base set of arcs represent a set of equivalent relationships, then neither of those relationships is included in the network of relationships associated with that base set of arcs. · Arc A with use="optional" and priority="1" represents relationship A · Arc B with use="prohibited" and priority="2" represents relationship B Arc B has the higher priority and represents a prohibiting relationship. Therefore relationship B excludes relationship A from the network of relationships associated with the base set of arcs. Relationship B is prohibiting and so, by definition, is excluded from the network of relationships associated with the base set of arcs (by application of rules i and iv). |
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If another arc is subsequently introduced into the base set of arcs as follows: · Arc C with use="prohibited" and priority="3" represents relationship C and relationship C is equivalent to the relationships A and B, then, since it has the highest priority, it is a prohibiting relationship. Therefore relationship C excludes relationship A from the network of relationships associated with the base set of arcs. Relationships B and C are prohibiting and so, by definition, are excluded from the network of relationships associated with the base set of arcs (by application of rules i and iv). |
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If another arc is subsequently introduced into the base set of arcs as follows: · Arc D with use="optional" and priority="4" represents relationship D and relationship D is equivalent to the relationships A, B and C, then, since it has the highest priority, it is an overriding relationship. Relationships A, B and C are therefore not included in the network of relationships associated with the base set of arcs. This relationship D thus effectively overrides the effect of the prohibiting relationships B and C and therefore is included in the network of relationships associated with the base set of arcs (by application of rule ii). |
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If another arc is subsequently introduced into the base set of arcs as follows: · Arc E with use="optional" and priority="4" represents relationship E and relationship E is equivalent to the relationships A, B, C and D, then, since it has the same priority as D, it is application dependent as to which of D and E is the overriding relationship. Relationships A, B and C are still not included in the network of relationships associated with the base set of arcs (by application of rule iii). Since the relationships are equivalent, the fact that it is application dependent as to which of D and E is the overriding relationship is unimportant because the choice of one over the other does not affect the semantics being expressed. |
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If another arc is subsequently introduced into the base set of arcs as follows: · Arc F with use="prohibited" and priority="4" represents relationship F and relationship F is equivalent to the relationships A, B, C, D and E, then, since it is one of the relationships with the highest priority, it is a prohibiting relationship and thus none of the equivalent relationships A, B, C, D, E or F are included in the network of relationships associated with the base set of arcs (by application of rule iv). |
The process of dividing all discovered arcs in a DTS into base sets and applying the rules of prohibition and overriding results in a set of networks of relationships, where each network contains relationships that:
· are represented by arcs that have the same local name, namespace and xlink:arcrole attribute value on the arcType element; and
· are represented by arcs that are contained in extendedType elements with the same local name, namespace, and xlink:role attribute value; and
· are not prohibited, prohibiting or overridden relationships.
To point to a particular XML element, URIs used in [XLINK] hrefs MUST end in a fragment identifier. According to the [XLINK] specification, XPointer [XPTR] syntax is allowed in the fragment identifier. The format of the fragment identifier MUST conform to the requirements set out for shorthand pointers (http://www.w3.org/TR/xptr-framework/#shorthand) or to the requirements set out for a scheme-based pointer (http://www.w3.org/TR/xptr-framework/#scheme). The only scheme allowed for scheme-based pointers in XBRL links is the element scheme [ELEMENT].
Example 7. Example xlink:href values
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Example |
Meaning |
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#f1 |
The fragment of the current document with an id attribute equal to “f1” |
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us_bs_v21.xsd#currentAssets |
The element of the document us_bs_v21.xsd with an id attribute equal to ”currentAssets” |
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us_bs_v21.xsd#element(/1/14) |
The element of the document us_bs_v21.xsd that is the 14 child (in document order) of the root element. |
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us_bs_v21.xsd#element(currentAssets) |
The element of the document us_bs_v21.xsd with an id attribute equal to ”currentAssets” |
An overview of XBRL instances is provided in Section 3.2.
XBRL instances are XML fragments with root element, xbrl. XBRL instances contain facts, with each fact corresponding to a concept defined in their supporting DTS. XBRL instances also contain context and unit elements that provide additional information needed to interpret the facts in the instance.
Facts can be simple, in which case their values are expressed as simple content (except in the case of simple facts whose values are expressed as a ratio), and facts can be compound, in which case their values are made up from other simple and/or compound facts. Simple facts are expressed using items (and are referred to as items in this specification) and compound facts are expressed using tuples (and are referred to as tuples in this specification).
Although the syntax for any given tuple or item can only be defined in a single taxonomy schema, an XBRL instance MAY contain XBRL items and tuples from any number of taxonomy schemas.
XBRL instances identify the taxonomy schemas and XBRL linkbases that make up the starting points for discovery of the DTS that supports them. Section 3.2 documents how the DTS supporting an XBRL instance is to be determined.
The taxonomy schemas and the linkbases used as starting points in DTS discovery are identified via the schemaRef elements and linkbaseRef elements in XBRL instances respectively. This enables XBRL instances to exert some control over the interpretation of the information that they report.
For example, the same set of elements defined in a taxonomy schema might have Spanish and Portuguese literature references defined in different linkbases (that are not referenced directly from that schema). An instance might provide access to both or neither of these linkbases in order to specify which set of references the producer considers to be more appropriate.
An XBRL instance MUST comply with the rules specified herein. The syntax for XBRL instances is constrained using a set of XML Schemas. Example elements defined in the XBRL instance schema, xbrl-instance-2003-12-31.xsd (normative), include xbrl, item, context, unit, and tuple. All XBRL instances MUST be valid XML documents as defined by XML Schema [SCHEMA‑1].
The semantics of XBRL instances and their contents are specified only insofar as they impact the operation of software applications that use this specification.
Expressing even a single fact in an XBRL instance requires multiple elements: at least one item element (see Section 4.1.1) and a context element containing sub-elements (see Section 4.7 below). Therefore, a container element is necessary to serve as the root element of an XBRL instance. This container is the xbrl element. If multiple “data islands” of XBRL mark-up are included in a larger document, the xbrl element is the container for each.
The XML Schema constraints on the xbrl element are shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/instance" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" elementFormDefault="qualified">
<element name="xbrl"> <annotation> <documentation> XBRL instance root element. </documentation> </annotation> <complexType> <sequence> <element ref="link:schemaRef" minOccurs="1" maxOccurs="unbounded" /> <element ref="link:linkbaseRef" minOccurs="0" maxOccurs="unbounded" /> <element ref="link:roleRef" minOccurs="0" maxOccurs="unbounded" /> <element ref="link:arcroleRef" minOccurs="0" maxOccurs="unbounded" /> <choice minOccurs="0" maxOccurs="unbounded"> <element ref="xbrli:item"/> <element ref="xbrli:tuple"/> <element ref="xbrli:context"/> <element ref="xbrli:unit"/> <element ref="link:footnoteLink"/> </choice> </sequence> <attribute name="id" type="ID" use="optional" /> <anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax" /> </complexType> </element>
</schema> |
Example 8. Use of xbrl as the root element
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<xbrl xmlns="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.xbrl.org/2001/XLink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ci="http://www.xbrl.org/us/gaap/ci/2003/usfr-ci-2003" xsi:schemaLocation=" http://www.xbrl.org/us/fr/ci/2003/usfr-ci-2003 http://www.xbrl.org/us/fr/ci/2000-07-31/usfr-ci-2003.xsd"> <link:schemaRef xlink:type="simple" xlink:href="http://www.xbrl.org/us/fr/ci/2000-07-31/usfr-ci-2003.xsd"/> <ci:assets precision="3" unitRef="u1" contextRef="c1">727</ci:assets> <ci:liabilities precision="3" unitRef="u1" contextRef="c1">635</ci:liabilities> <context id="c1"><!-- ... --></context> <unit id="u1"><!-- ... --></unit> </xbrl> |
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Meaning: xbrl holds namespace prefix definitions and the schemaLocation attribute. |
The xbrl element MAY have an id attribute. The value of the id attribute MUST conform to the [XML] rules for attributes with the ID type (http://www.w3.org/TR/REC-xml#NT-TokenizedType).
The xbrl element MAY have an xml:base attribute. The xml:base attribute [XML Base] MAY appear on the xbrl element, participating in the resolution of relative URIs in the XBRL instance.
Every XBRL instance MUST contain at least one schemaRef element. The schemaRef element is a simple link, as defined in Section 3.5.1. The schemaRef element MUST occur as a child element of an xbrl element. All schemaRef elements in an XBRL instance MUST occur before other children of the xbrl element, in document order.
In an XBRL instance, the schemaRef element points to a taxonomy schema that becomes part of the DTS supporting that XBRL instance.
NOTE: XBRL instance creators should be aware that, if there are inconsistencies between the information conveyed by a schemaRef element and that conveyed by schemaLocation attributes elsewhere in the instance, processors may have difficulty processing the instance correctly.
The XML Schema definition of the schemaRef element is shown below.
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<schema targetNamespace="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
<complexType name="simpleType"> <annotation> <documentation> Type for the simple links defined in XBRL </documentation> </annotation> <complexContent> <restriction base="anyType"> <attributeGroup ref="xlink:simpleType"/> <attribute ref="xlink:href" use="required" /> <attribute ref="xlink:arcrole" use="optional" /> <attribute ref="xlink:role" use="optional" /> <attribute ref="xlink:title" use="optional" /> <attribute ref="xlink:show" use="optional" /> <attribute ref="xlink:actuate" use="optional" /> <anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax" /> </restriction> </complexContent> </complexType>
</schema>
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<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="schemaRef" type="xl:simpleType" substitutionGroup="xl:simple"> <annotation> <documentation> Definition of the schemaRef element - used to link to XBRL taxonomy schemas from XBRL instances. </documentation> </annotation> </element>
</schema> |
The xlink:type attribute MUST occur and MUST have the fixed content “simple”.
A schemaRef element MUST have an xlink:href attribute. The xlink:href attribute MUST be a URI. The URI MUST point to an XML Schema. If the URI reference is relative, its absolute version MUST be determined as specified in [XML Base] before use. For details on the allowable forms of XPointer [XPTR] syntax in the URI see section 3.5.4.
The xlink:arcrole attribute MAY be used on the schemaRef element. It is given no semantics by this specification. The xlink:arcrole attribute value MUST be a URI value as defined by the [XLINK] specification.
The xlink:role attribute MAY be used on the schemaRef element. No semantics are defined for the xlink:role attribute when it occurs on the schemaRef element. The xlink:role attribute value MUST be a URI value as defined by the [XLINK] specification.
The xml:base attribute [XML Base] MAY appear on schemaRef elements, participating in the resolution of relative URIs specified in their xlink:href attributes.
The [XLINK] specification provides for a standard way of finding linkbases (See http://www.w3.org/TR/xlink/#xlg). The linkbaseRef element conforms to this standard by using a specific xlink:arcrole content value (See Section 4.3.3).
One or more linkbaseRef elements MAY occur as children of the xbrl element (They MAY also occur in taxonomy schemas. See Section 5.1.2 for details). If linkbaseRef elements occur as children of xbrl elements, they MUST follow the schemaRef elements and precede all other elements, in document order.
In an XBRL instance, the linkbaseRef element identifies a linkbase that becomes part of the DTS supporting that XBRL instance.
The XML Schema constraints applying to the linkbaseRef element are shown below.
|
<schema targetNamespace="http://www.xbrl.org/2003/linkbase" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:xlink="http://www.w3.org/1999/xlink" elementFormDefault="qualified">
<element name="linkbaseRef" substitutionGroup="xl:simple"> <annotation> <documentation> Definition of the linkbaseRef element - used to link to XBRL taxonomy extended links from taxonomy schema documents and from XBRL instances. </documentation> </annotation> <complexType> <complexContent> <restriction base="xl:simpleType"> <attribute ref="xlink:arcrole" use="required"> <annotation> <documentation> This attribute must have the value: http://www.w3.org/1999/xlink/properties/linkbase </documentation> </annotation> </attribute> <anyAttribute namespace="http://www.w3.org/XML/1998/namespace" processContents="lax" /> </restriction> </complexContent> </complexType> </element>
</schema> |
The xlink:type attribute MUST occur and MUST have the fixed content “simple”.
A linkbaseRef element MUST have an xlink:href attribute. The xlink:href attribute MUST be a URI. The URI MUST point to a linkbase (as defined in Section 3.5.2) that contains the appropriate extended links, as determined by the value of the xlink:role attribute. If the URI reference is relative, its absolute version MUST be determined as specified in [XML Base] before use. For details on the allowable forms of XPointer [XPTR] syntax in the URI see section 3.5.4.
To indicate that the linkbaseRef element points to a linkbase, the xlink:arcrole attribute on the linkbaseRef element MUST have the [XLINK]- specified fixed content:
http://www.w3.org/1999/xlink/properties/linkbase
The optional xlink:role attribute constrains the kinds of extended links that are permitted within the linkbase identified by the linkbaseRef element. Table 2 sets out the standard xlink:role attribute values for the xlink:role attribute when it occurs on the linkbaseRef element. Table 2 also documents which kinds of extended links:
· MUST be contained by the linkbase connected to by a linkbaseRef element with each of the standard xlink:role attribute values; and
· MUST NOT be contained by the linkbase connected to by a linkbaseRef element with each of the standard xlink:role attribute values.
If a linkbaseRef element connects to a linkbase containing an extended link that has not been defined in this specification, then a non-standard value of the xlink:role attribute MAY be used or the xlink:role attribute MAY be omitted.
Table 2. Roles in the linkbaseRef element
|
Values of the linkbaseRef xlink:role attribute |
Element pointed to by xlink:href |
|
(unspecified) |
MAY contain any extended link elements |
|
http://www.xbrl.org/2003/role/calculationLinkbaseRef |
MUST contain only calculationLink elements |
|
http://www.xbrl.org/2003/role/definitionLinkbaseRef |
MUST contain only definitionLink elements |
|
http://www.xbrl.org/2003/role/labelLinkbaseRef |
MUST contain only labelLink elements |
|
http://www.xbrl.org/2003/role/presentationLinkbaseRef |
MUST contain only presentationLink elements |
|
http://www.xbrl.org/2003/role/referenceLinkbaseRef |
MUST contain only referenceLink elements |
The xml:base attribute [XML Base] MAY appear on linkbaseRef elements, participating in the resolution of relative URIs specified in their xlink:href attributes.
One or more roleRef elements (defined in Section 3.5.2.4) MAY be used in XBRL instances. If used, they MUST appear immediately after the linkbaseRef elements in the XBRL instance, in document order. roleRef elements are used in XBRL instances to reference the definitions of any custom xlink:role attribute values used in footnote links in the XBRL instance.
One or more arcroleRef elements (defined in Section 3.5.2.5) MAY be used in XBRL instances. If used, they MUST appear immediately after the roleRef elements in the XBRL instance, in document order. arcroleRef elements are used in XBRL instances to reference the definitions of any custom xlink:arcrole attribute values used in footnote links in the XBRL instance.
As discussed in Section 3 above, an item represents a single fact or business measurement. In the XML Schema for XBRL instances, item is defined as an abstract element. This means that it will never appear in its own right in an XBRL instance. Therefore, all elements representing single facts or business measurements defined in an XBRL taxonomy document and reported in an XBRL instance MUST be either (a) members of the substitution group item; or, (b) members of a substitution group originally based on item. XBRL taxonomies include taxonomy schemas that contain such element definitions. item elements might need to be referenced from elsewhere (such as from a footnote) therefore taxonomy authors SHOULD NOT prohibit the id attribute inherited from the base XBRL item type.
item elements MUST NOT be descendants of other item elements. Structural relationships necessary in an XBRL instance MUST be captured only using tuples (see Section 4.9). The intellectual structure – the relationship of financial concepts to each other in a variety of senses – is captured by the link structure of taxonomy linkbases rather than by nesting of facts in XBRL instances.
The XML Schema definition of the item element and the data types for elements in the item substitution group are given below.
|
<schema targetNamespace="http://www.xbrl.org/2003/instance" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" elementFormDefault="qualified">
<attributeGroup name="numericItemAttrs"> <annotation> <documentation> Group of attributes for numeric items </documentation> </annotation> <attribute name="contextRef" type="IDREF" use="required" /> <attribute name="unitRef" type="IDREF" use="required" /> <attribute name="precision" type="xbrli:precisionType" use="optional" /> <attribute name="decimals" type="xbrli:decimalsType" use="optional" /> <attribute name="id" type="ID" use="optional" /> </attributeGroup>
<attributeGroup name="nonNumericItemAttrs"> <annotation> <documentation> Group of attributes for non-numeric items </documentation> </annotation> <attribute name="contextRef" type="IDREF" use="required" /> <attribute name="id" type="ID" use="optional" /> </attributeGroup>
<annotation> <documentation> XBRL domain numeric item types - for use on concept element definitions The following 4 numeric types are all types that have been identified as having particular relevance to the domain space addressed by XBRL and are hence included in addition to the built-in types from XML Schema. </documentation> </annotation>
<complexType name="monetaryItemType" final="extension"> <simpleContent> <extension base="xbrli:monetary"> <attributeGroup ref="xbrli:numericItemAttrs" /> <anyAttribute namespace="##other" processContents="lax" /> </extension> </simpleContent> </complexType>
<complexType name="sharesItemType" final="extension"> <simpleContent> <extension base="xbrli:shares"> <attributeGroup ref="xbrli:numericItemAttrs" /> <anyAttribute namespace="##other" processContents="lax" /> </extension> </simpleContent> </complexType>
<complexType name="pureItemType" final="extension"> <simpleContent> <extension base="xbrli:pure"> <attributeGroup ref="xbrli:numericItemAttrs" /> <anyAttribute namespace="##other" processContents="lax" /> </extension> </simpleContent> </complexType>
<element name="numerator" type="decimal" /> <element name="denominator" type="xbrli:nonZeroDecimal" /> <complexType name="fractionItemType" final="extension"> <sequence> <element ref="xbrli:numerator" /> <element ref="xbrli:denominator" /> </sequence> <attribute name="contextRef" type="IDREF" use="required" /> <attribute name="unitRef" type="IDREF" use="required" /> <attribute name="id" type="ID" use="optional" /> <anyAttribute namespace="##other" processContents="lax" /> </complexType>
<complexType name="stringItemType" final="extension"> <simpleContent> <extension base="string"> <attributeGroup ref="xbrli:nonNumericItemAttrs" /> <anyAttribute namespace="##other" processContents="lax" /> </extension> </simpleContent> </complexType>
<!-- booleanItemType, hexBinaryItemType, base64BinaryItemType, anyURIItemType, , QNameItemType, durationItemType, dateTimeItemType, timeItemType, dateItemType, gYearMonthItemType, gYearItemType, gMonthDayItemType, gDayItemType, gMonthItemType, normalizedStringItemType, tokenItemType, languageItemType, NameItemType, ... -->
<element name="item" type="anyType" abstract="true"> <annotation> <documentation> Abstract item element used as head of item substitution group </documentation> </annotation> </element>
</schema> |
Example 9. A numeric fact with three significant digits
|
<ci:capitalLeases contextRef="c1" unitRef="u1" precision="3">727432</ci:capitalLeases> |
|
Meaning: The value of Capital Leases in the numeric context labelled c1 is 727000 accurate to 3 significant figures. Note that it will be necessary to consult the context (defined below) in order to determine other details concerning the value such as entity, period, etc. and it will be necessary to consult the referenced unit element to determine the relevant unit information. |
Example 10. A non-numeric item
|
<ci:concentrationsNote contextRef="c1"> Concentration of credit risk with regard to short term investments is not considered to be significant due to the Company's cash management policies. These policies restrict investments to low risk, highly liquid securities (that is, commercial paper, money market instruments, etc.), outline issuer credit requirements, and limit the amount that may be invested in any one issuer. </ci:concentrationsNote> |
|
Meaning: The text of the Concentrations note in the context labelled c1. |
The content of the abstract item element is derived from anyType. Each member of the substitution group of item must have a defined XBRL item type. This allows each substitution for item in the instance to validate against its own data type. There is one defined XBRL item type derived from each of the appropriate built-in types of XML Schema, along with the fractionItemType type. The complete list is in Section 5.1.1.3. An item MUST NOT have complex content unless its item type is derived by restriction from fractionItemType.
The contextRef attribute is an IDREF to the context element (see Section 4.7) that holds additional relevant information about the fact represented. An item MUST contain a contextRef attribute that references a context element in the same XBRL instance. Note that an XBRL instance is an occurrence of the xbrl element, not the entire document. Items whose content is derived from an XML Schema built-in numeric type (decimal, float or double or a built-in type derived from one of them) or fractionItemType by restriction MUST use the contextRef attribute and the unitRef attribute; all others MUST use the contextRef attribute.
The unitRef attribute is an IDREF to the unit element (see Section 4.8) that holds information about units in which numeric facts have been measured. The unitRef attribute MUST NOT occur in non-numeric items. The unitRef attribute MUST occur in numeric items, referencing a unit element in the same XBRL instance.
Two optional attributes, precision and decimals, are available on numeric items (except those with type fractionItemType) to enable the XBRL instance creator to make statements about the accuracy of the facts represented. They are discussed in the following sections.
All items MUST have a context. All tuples MUST NOT have a context. Items identify their contexts using the contextRef attribute. The contextRef attribute is used to identify the context element that is associated with the item on which the contextRef attribute occurs.
The value of the contextRef attribute MUST be equal to the value of an id attribute on a context element in the XBRL instance that contains the item on which the contextRef attribute occurs.
All numeric items MUST have a statement of the units of measurement. All tuples and all non-numeric items MUST NOT have a statement of the units of measurement. Numeric items identify their units using the unitRef attribute. The unitRef attribute is used to identify the unit element that is associated with the item on which the unitRef attribute occurs.
The value of the unitRef attribute MUST be equal to the value of an id attribute on a unit element in the XBRL instance that contains the numeric item on which the unitRef attribute occurs.
A numeric item MUST have either a precision attribute or a decimals attribute unless it is of the fractionItemType or of a type that is derived by restriction from fractionItemType or has a nil value, in which case, it MUST NOT have either a precision attribute or a decimals attribute.
A numeric item MUST NOT have both a precision attribute and a decimals attribute.
A non-numeric item MUST NOT have either a precision or a decimals attribute.
When determining whether two numeric items are v-equal (a predicate that is used in the definition of various other equality type predicates) it is necessary to take into consideration the values of precision (or the precision inferred from the value of the decimals attribute) for the two numeric items. The formal definition of v-equal for two numeric items is given in Section 4.10.
The precision attribute MUST be a non-negative integer or the string "INF" that conveys the arithmetic precision of a measurement, and, therefore, the utility of that measurement to further calculations. Different software packages may claim different levels of accuracy for the numbers they produce. The precision attribute allows any producer to state the precision of the output in the same way. If a numeric fact has a precision attribute that has the value “n” then it is correct to “n” significant figures (See Section 4.6.1 for the normative definition of ‘correct to “n” significant figures’). An application SHOULD ignore (i.e. replace with zeroes) any digits after the first “n” decimal digits, counting from the left, starting at the first non-zero digit in the lexical representation of any number for which the value of precision is specified or inferred to be n.
The meaning of precision="INF" is that the lexical representation of the number is the exact value of the fact being represented.
Example 11. Precision and lexical representation
|
Example |
Meaning |
|
precision="9" |
Precision of nine digits. The first 9 digits, counting from the left, starting at the first non-zero digit in the lexical representation of the value of the numeric fact are known to be trustworthy for the purposes of computations to be performed using that numeric fact. |
|
Precision |
Example |
Read as |
Known to be GE |
Known to be LT |
|
INF |
476.334 |
476.334 |
476.334 |
476.33400000000…1 |
|
3 |
205 |
205e0 |
204.5 |
205.5 |
|
4 |
2002000 |
2002e3 |
2001500 |
2002500 |
|
2 |
2012 |
20e2 |
1950 |
2050 |
|
2 |
2000 |
20e2 |
1950 |
2050 |
|
1 |
99 |
1e2 |
95 |
105 |
|
0 |
1234 |
1234 |
unknown |
Unknown |
The simple type precisionType has been provided to define the value space for the value of the precision attribute. Its definition is as follows:
|
<schema targetNamespace="http://www.xbrl.org/2003/instance" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" elementFormDefault="qualified">
<simpleType name="precisionType"> <annotation> <documentation> This type is used to specify the value of the precision attribute on numeric items. It consists of the union of nonNegativeInteger and "INF" (used to signify infinite precision or "exact value"). </documentation> </annotation> <union memberTypes="nonNegativeInteger"> <simpleType> <restriction base="string"> <enumeration value="INF" /> </restriction> </simpleType> </union> </simpleType>
</schema> |
The decimals attribute MUST be an integer or the value "INF" that specifies the number of decimal places to which the value of the fact represented may be considered accurate, possibly as a result of rounding or truncation. If a numeric fact has a decimals attribute with the value “n” then it is known to be correct to “n” decimal places. (See section 4.6.7.2 for the normative definition of ‘correct to “n” decimal places’).
The meaning of decimals="INF" is that the lexical representation of the number is the exact value of the fact being represented.
Example 12. Decimals and lexical representation
|
Example |
Meaning |
|
decimals="2" |
The value of the numeric fact is known to be correct to 2 decimal places. |
|
decimals="-2" |
The value of the numeric fact is known to be correct to –2 decimal places, i.e. all digits to the left of the hundreds digit are accurate. |
|
Decimals |
Original |
Read as |
Known to be GE |
Known to be LT |
|
INF |
436.749 |
436.749 |
436.749 |
436.74900000…1 |
|
2 |
10.00 |
10.00 |
9.995 |
10.005 |
|
2 |
10 |
10.00 |
9.995 |
10.005 |
|
2 |
10.000 |
10.00 |
9.995 |
10.005 |
|
2 |
10.009 |
10.01 |
10.005 |
10.015 |
|
0 |
10 |
10. |
9.5 |
10.5 |
|
-1 |
10 |
10. |
5 |
15 |
|
-1 |
11 |
10. |
5 |
15 |
|
3 |
205 |
205.000 |
204.9995 |
205.0005 |
|
4 |
2002000 |
2002000.0000 |
2001999.99995 |
2002000.00005 |
|
-2 |
205 |
200. |
150 |
250 |
|
-2 |
2002000 |
2002000. |
2001950 |
2002050 |
|
-3 |
2002000 |
2002000. |
2001500 |
2002500 |
|
-4 |
2002000 |
2000000. |
1995000 |
2005000 |
|
-3 |
777000 |
777000 |
776500 |
777500 |
The simple type decimalsType defines the legal values for the decimals attribute. Its XML Schema definition is as follows:
|
<schema targetNamespace="http://www.xbrl.org/2003/instance" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" elementFormDefault="qualified">
<simpleType name="decimalsType"> <annotation> <documentation> This type is used to specify the value of the decimals attribute on numeric items. It consists of the union of integer and "INF" (used to signify that a number is expressed to an infinite number of decimal places or "exact value"). </documentation> </annotation> <union memberTypes="integer "> <simpleType> <restriction base="string"> <enumeration value="INF" /> </restriction> </simpleType> </union> </simpleType>
</schema> |
The following rules enable XBRL instance consumers to infer a value for the precision attribute of a numeric item when none is supplied.
For a numeric item of type fractionItemType or type derived by restriction from fractionItemType, a consuming application MUST infer the precision to be equal to 'INF' if it is to be used in calculations.
If, on a numeric item, the decimals attribute is present rather than the precision attribute, then a consuming application MUST infer the precision of that numeric fact if it is to be used in calculations or searches for duplicates in XBRL instances.
Given the value of the decimals attribute, the precision of a numeric item is equal to n, where n is equal to the maximum of 0 and the result of the following calculation:
if there are non-zero digits to the left of the decimal point or implied decimal point if absent then the number of digits excluding any leading zeros to the left of the decimal point (or implied decimal point if absent) in the lexical representation of the numerical fact
otherwise if there are non-zero digits to the right of the decimal point, the negative of the number of zeros between the decimal point and the first non-zero digit in the lexical representation of the numerical fact
otherwise zero
plus
the value of the exponent in the lexical representation of the numerical fact
(if present)
plus
the number of decimal places to which the numeric fact is known to be correct.
Example 13. Lexical representation, precision and decimals
|
123.45e5 |
-3 |
3+5+(-3)=5 |
The following definitions are provided for clarity regarding accuracy-related features of this specification, i.e. precision and decimals attributes.
If a the lexical representation of the value of a number is said to be correct to n significant figures it means that the first “n” decimal digits, counting from the left, starting at the first non-zero digit in the lexical representation of the number are known to be accurate for the purposes of computations to be performed using that number. (Note: in the following it is assumed that all zeros to the left of the decimal point and to the left of the first non-zero digit in the decimal representation have been removed first).
More precisely: in the decimal representation of a number, a significant figure is any one of the digits 1, 2, 3...9 that specify the magnitude of a number. Zero (0) is a significant figure except when it appears to the left of all non-zero digits or is used solely to fill the places of unknown or discarded digits (after truncation or rounding - see later). Thus, in the number "0.00263", there are three significant figures: 2, 6, and 3. The zeroes are not significant. In the number "3809" all four of the digits are significant. In the number "46300" the digits 4, 6, and 3 are known to be significant but it is not possible to conclude anything concerning the two zeroes as they are written. This ambiguity can be removed by writing the number in terms of powers of ten. If there are three significant figures the representation becomes 4.63 × 104; if there are four significant figures it becomes 4.630 × 104, etc.
It is often necessary to round significant figures following a calculation. This is known as rounding. To round a number to n significant figures, discard all digits to the right of the nth place. This step is known as truncation. Then, if the left-most discarded digit is less than 5, leave the nth digit unchanged; if the left-most discarded digit is greater than or equal to 5, add 1 to the nth digit (propagating any carries to digits further to the left according to the normal rules of arithmetic and removing the final 0 if necessary). For example:
Example 14. Rounding
|
Original |
Rounded to n significant figures |
|
|
|
n=2 |
n=3 |
|
3.5643 |
3.6 |
3.56 |
|
3.5673 |
3.6 |
3.57 |
|
0.49787 |
0.50 |
0.498 |
|
3.9999 |
4.0 |
4.00 |
|
9.999991 |
10 |
10.0 |
|
22.55 |
23 |
22.6 |
|
0.0019 |
0.0019 |
0.00190 |
|
0.00002 |
0.000020 |
0.0000200 |
The same procedure MAY be followed for any value of n, and we then say that a particular lexical representation of the value of a number is correct to n significant figures.
If the representation of a number is correct to n decimal places then the absolute difference between the value of the number and its representation (known as the “absolute error” of the representation - eabs) is less than or equal to 0.5 x 10-n. n may be a positive or negative integer or zero.
Mathematically this may be expressed as follows:
For the number X, x is a representation of X correct to n decimal places if and only if
eabs = |X-x| £ 0.5 ´ 10-n
or, because of rounding conventions,
-0.5 ´ 10-n £ x-X < 0.5 ´ 10-n
Rounding, as described earlier, can be used to make a number correct to exactly n decimal places. The following table shows the representations of the number 123456.789012 correct to various numbers of decimal places:
Example 15. Correct to n decimal places
|
123456.789012 correct to n decimal places |
||||
|
n=-3 |
n=-2 |
n=0 |
n=3 |
n=6 |
|
123000 |
123500 |
123457 |
123456.789 |
123456.789012 |
The context element contains information about the entity being described, the reporting period and the reporting scenario, all of which are necessary for understanding a business fact captured as an XBRL item.
The context element MUST conform to the following XML Schema constraints:
|
<schema targetNamespace="http://www.xbrl.org/2003/instance" xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" elementFormDefault="qualified">
<element name="context"> <annotation> <documentation> Used for an island of context to which facts can be related. </documentation> </annotation> <complexType> <sequence> <element name="entity" type="xbrli:contextEntityType" /> <element name="period" type="xbrli:contextPeriodType" /> <element name="scenario" type="xbrli:contextScenarioType" minOccurs="0" /> </sequence> <attribute name="id" type="ID" use="required" /> </complexType> </element>
</schema> |
In the examples provided in the following sub-sections, the xsi:schemaLocation attribute does not contain URIs to resolve the ISO4217 and NASDAQ namespaces. In the case of NASDAQ the examples assume that the applications that produced and will consume this instance will be able to resolve this namespace reference without the help of the xsi:schemaLocation. The ISO4217 namespace does not refer to an XML Schema that can be used for validation of the XBRL instances shown in the examples. The ISO4217 and NASDAQ URIs do not reference actual resources of the ISO or NASDAQ.
Every context element MUST include the id attribute. The content of the id attribute MUST conform to the [XML] rules for attributes with the ID type (http://www.w3.org/TR/RE