1 Goals

XBRL provides a set of standard units that may appear in XBRL instances. These include those specified in [XBRL 2.1]. As XBRL applications have emerged, unit declarations have appeared in XBRL instance documents having multiple names for equivalent meanings, and identical names having different meanings. The goal of the XBRL Units Registry (hereinafter "UTR") is to be a public, online data set that documents these units and their usage. Additions and other changes to the UTR, like other XBRL International work products, will proceed through a series of steps whose goal is to maximise the utility and longevity of the new units and the instances that use them. This process is documented in [UTR PROCESS].

1.1 Relationship to other work

This document pertains to XBRL as defined in the XBRL Specification [XBRL 2.1].

1.2 Terminology

The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, in this specification, are to be interpreted as described in [IETF RFC 2119].

abstract element, bind, concept, concrete element, context, Discoverable Taxonomy Set (DTS), duplicate items, duplicate tuples, element, entity, equal, essence concept, fact, instance, item, least common ancestor, linkbase, period, taxonomy, tuple, unit, taxonomy schema, child, parent, sibling, grandparent, uncle, ancestor, XBRL instance, c-equal, p-equal, s-equal, u-equal, v-equal, x-equal, minimally conforming XBRL processor, fully conforming XBRL processor and any other terms not specifically defined elsewhere in this document but which are used and defined in the XBRL 2.1 specification. are as defined by [XBRL 2.1] .

BPB refers to the XBRL International Best Practices Board .

CR refers to a Candidate Recommendation of XBRL International.

ISC refers to the XBRL International Steering Committee .

IWD refers to an Internal Working Draft of XBRL International.

DTR refers to the Data Types Registry that is the subject of a different specification.

UTR refers to the Units Registry that is the subject of this specification.

UTRAM refers to the Units Registry Approval Manager.

PWD refers to a Public Working Draft of XBRL International.

Referee is either the SWG or TAPWG when performing an evaluation requested by the UTRAM.

SWG refers to the XBRL International Base Specification and Maintenance Working Group.

TAPWG refers to the Taxonomy Architecture Practice Working Group set up by the BPB.

TRTF refers to the Taxonomy Review Task Force set up by the BPB.

XSB refers to the XBRL International Standards Board .

1.3 Language

The official language of XBRL International's own work products is English and the preferred spelling convention is UK English.

All documentation supporting a registry entry MUST be provided in English, and MAY be provided in additional languages.

1.4 Document conventions

1.4.1 Typographic conventions

1.4.1.1 Definition notation

Definitions are highlighted with green text.

1.4.1.2 Footnote notation

Comments which are informative, but not essential to the understanding of the point at hand, are provided in footnotes. All footnotes are non-normative.

1.4.1.3 Element and attribute notation

When referring to a specific element, it will be identified by its namespace prefix and local name. For example, the root element for a specification container element would be referred to as <variable:generalVariable>.

Attributes are also identified by their local name and, where appropriate, their namespace prefix. Attributes are distinguished from elements by prefixing them by an @ symbol. Thus, @id refers to the attribute with the name id.

When referring to any attribute, so long as it has a specific namespace, the local name is replaced by an asterisk ( *). Thus, the notation @xml:* specifies any attribute in the namespace http://www.w3.org/XML/1998/namespace.

1.4.2 Formatting conventions

The following highlighting is used for normative technical material in this document:

Example 1: A normative example

Text of the normative example.

The following highlighting is used for non-normative examples in this document:

Example 2: A non-normative example

Text of the helpful example.

Next paragraph of the helpful example.

Example 3 shows the formatting for non-normative examples of poor, discouraged or disallowed usage.

Example 3: An example of poor usage

The example itself.

2 Data Model

The data model of the UTR is a list of each unit definition augmented with additional indicators and information needed by developers.

Table 1: A UTR entry

Field	Min	Max	Type	Explanation	Example(s)
ID	1	1	ID	The ID attribute of this entry, unique within the scope of the Units Registry.	u00256
Unit ID	1	1	string	The identifier to be used in the id attribute of the xs:unit declaration of instances. It will not be unique in the scope of the UTR because there could be (for example) a REC definition of a unit, and an IWD version of it.	GBP; sqft; MMBbls
Unit Name	1	1	string	The name of the unit being defined, which may have spaces and other characters and is conventionally in Proper Case.	Square Foot; Thousands of Barrels of Oil
Unit Namespace	0	1	URI	The namespace in which the unit is declared in a xbrli:measure element. If absent, it means that the unit is not a simple measure.	http://www.xbrl.org/2009/utr
Item Type	0	1	NCName	The local-name of a type with which this unit may be used.	areaItemType
Item Type Namespace	0	1	URI	Item type namespace; absent if the namespace does not matter.	http://www.xbrl.org/dtr/type/numeric
Item Type Date	0	1	date	Version date of the XBRL specification or data type registry in which the item type first appears, or empty if the type is not yet present	2009-12-16
Symbol	0	1	NMTOKEN	The symbol used when rendering figures measured in the unit. This may be unicode such as a currency symbol. Monetary symbols are conventionally displayed before a number; other symbols conventionally displayed after.	m³; Å; €
Numerator Item Type	0	1	NCName	If the unit name contains "{numerator}" then the unit numerator must be for a unit that is compatible with this item type local name.	lengthItemType
Numerator Item Type Namespace	0	1	URI	If the namespace of the numerator item type is limited, then it is provided here.	http://www.xbrl.org/dtr/type/numeric
Denominator Item Type	0	1	NCName	If the unit name contains {denominator} then the unit denominator must be for a unit that is compatible with this item type.	sharesItemType
Denominator Item Type Namespace	0	1	URI	If the namespace of the denominator item type is limimted, then it is provided here.	http://www.xbrl.org/2003/instance
Definition	1	1	XHTML mixed	The meaning of the unit, in English.	Millions of US Gallons per Day (Volumetric Flow)
Base Standard	0	1	{ISO4217, SI, Customary, Non-SI, XBRL}	A token indicating the authority or source, such as an [ISO] code list, of the unit definition.	SI
Presentation Conversion	0	1	XML	MathML definition using elements such as mrow and msup to present a formula for conversion into standard international base units, if such a conversion exists.	<math> <mrow> <mn> 4046.86 </mn> <mo> * </mo> <msup> <mi> m </mi> <mn> 2 </mn> </msup> </mrow> </math>
Content Conversion	0	1	XML	MathML definition using elements such as apply, power and times to present a formula for conversion into standard international base units, if such a conversion exists.	<math> <apply> <times/> <cn> 4046.86 </cn> <apply> <power/> <ci> m </ci> <cn> 2 </cn> </apply> </apply> </math>
Status	1	1	{CR, REC, NIE, PROPOSED, ACK, RR}	The XBRL International status of this unit. CR - Candidate Recommendation REC - RECOMMENDATION NIE - Not in effect (for whatever reason other than RR such as being withdrawn, superseded, found to be invalid etc.) PROPOSED - Submitted but with no official status yet granted by XBRL International ACK - Acknowledged by XBRL International (indicates that the unit is not being considered for REC status but is listed in the UTR for information purposes) RR - Rescinded RECOMMENDATION	PROPOSED
Version Date	1	1	date	Effective date of this version of the unit; all versions of the same unit with earlier dates are effectively superseded.	2012-12-21

3 Hosting on the XBRL.org website

The latest version of the UTR will be placed at a fixed location on the xbrl.org website and will be the file at the URL http://www.xbrl.org/utr/utr.xml. Each version will also be permanently archived in a subdirectory whose name contains the date on which it became effective (e.g. http://www.xbrl.org/utr/2009-01-22/utr.xml). This is analogous to the archival convention for specification schemas.

4 Status of Units in the UTR and Implications for Software

The definition of any unit that has the status of REC in the UTR is normative.

The definitions of any units with any other status are non-normative and are provided for information only. If a unit has the status of ACK it is not intended that it should ever proceed on the track to having REC status. It MAY have a status in a closed environment that imposes certain requirements on software that is customised for that particular environment, however XBRL International makes no representations whatsoever about such units.

Software vendors are NOT obliged to implement support for any REC unit in order to continue to claim that they support the base specification.

It is expected that software vendors will make claims regarding which additional units they support. They MUST point to successful exercise of any relevant conformance suite tests in order to substantiate such claims.

Appendix A Schema

The following is the XML schema corresponding to the data model described in Section 2. It is normative. Non-normative versions (which should be identical to this except for appropriate comments indicating their non-normative status) are also provided as separate files for convenience of users of the specification.

Following the schema maintenance policy of XBRL International, it is the intent (but is not guaranteed) that the location of non-normative versions of these schemas on the web will be as follows: While any

While any schema is the most current RECOMMENDED version and until it is superseded by any additional errata corrections a non-normative version will reside on the web at: http://www.xbrl.org/utr/utr.xsd
A non-normative version of each schema as corrected by this update to the RECOMMENDATION will be archived in perpetuity on the web at: http://www.xbrl.org/utr/2011-05-05/utr.xsd

A.1 utr.xsd

<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:utr="http://www.xbrl.org/2009/utr"
xmlns:xhtml="http://www.w3.org/1999/xhtml" targetNamespace="http://www.xbrl.org/2009/utr" elementFormDefault="qualified" attributeFormDefault="unqualified">

<xs:import namespace="http://www.w3.org/1998/Math/MathML" schemaLocation="http://www.w3.org/Math/XMLSchema/mathml2/mathml2.xsd"/>

<xs:complexType name="DocumentationType" mixed="true">

<xs:annotation>

<xs:documentation>

Element type that may contain mixed text and XHTML markup

</xs:documentation>

</xs:annotation>

<xs:complexContent mixed="true">

<xs:restriction base="xs:anyType">

<xs:sequence minOccurs="0" maxOccurs="unbounded">

<xs:any namespace="http://www.w3.org/1999/xhtml" processContents="lax"/>

</xs:sequence>

</xs:restriction>

</xs:complexContent>

</xs:complexType>

<xs:group name="unitGroup">

<xs:sequence>

<xs:element ref="utr:unitId"/>

<xs:element ref="utr:unitName"/>

<xs:element ref="utr:nsUnit"/>

<xs:element ref="utr:itemType" minOccurs="0"/>

<xs:element ref="utr:nsItemType" minOccurs="0"/>

<xs:element ref="utr:itemTypeDate" minOccurs="0"/>

<xs:element ref="utr:symbol" minOccurs="0"/>

<xs:group ref="utr:numeratorGroup" minOccurs="0"/>

<xs:group ref="utr:denominatorGroup" minOccurs="0"/>

<xs:element ref="utr:definition"/>

<xs:element ref="utr:baseStandard"/>

<xs:element ref="utr:conversionPresentation" minOccurs="0" maxOccurs="1"/>

<xs:element ref="utr:conversionContent" minOccurs="0" maxOccurs="1"/>

<xs:element ref="utr:status"/>

<xs:element ref="utr:versionDate"/>

</xs:sequence>

</xs:group>

<xs:group name="numeratorGroup">

<xs:sequence>

<xs:element ref="utr:numeratorItemType" minOccurs="0">

<xs:annotation>

<xs:documentation>

If the unit name contains "{numerator}" then the unit numerator must be for a unit that is compatible with this item type local name.

</xs:documentation>

</xs:annotation>

</xs:element>

<xs:element ref="utr:nsNumeratorItemType" minOccurs="0">

<xs:annotation>

<xs:documentation>

If the namespace of the numerator item type is limited, then it is provided here.

</xs:documentation>

</xs:annotation>

</xs:element>

</xs:sequence>

</xs:group>

<xs:element name="numeratorItemType" type="xs:NCName">

<xs:annotation>

<xs:documentation>

If the unit name contains {numerator} then the unit numerator must be for a unit that is compatible with this item type.

</xs:documentation>

</xs:annotation>

</xs:element>

<xs:element name="nsNumeratorItemType" type="xs:anyURI">

<xs:annotation>

<xs:documentation/>

</xs:annotation>

</xs:element>

<xs:group name="denominatorGroup">

<xs:sequence>

<xs:element ref="utr:denominatorItemType" minOccurs="0">

<xs:annotation>

<xs:documentation>

If the unit name contains {denominator} then the unit denominator must be for a unit that is compatible with this item type.

</xs:documentation>

</xs:annotation>

</xs:element>

<xs:element ref="utr:nsDenominatorItemType" minOccurs="0">

<xs:annotation>

<xs:documentation>

If the namespace of the denominator item type is limimted, then it is provided here.

</xs:documentation>

</xs:annotation>

</xs:element>

</xs:sequence>

</xs:group>

<xs:element name="denominatorItemType" type="xs:NCName">

<xs:annotation>

<xs:documentation>

If the unit name contains {denominator} then the unit denominator must be for a unit that is compatible with this item type.

</xs:documentation>

</xs:annotation>

</xs:element>

<xs:element name="nsDenominatorItemType" type="xs:anyURI">

<xs:annotation>

<xs:documentation/>

</xs:annotation>

</xs:element>

<xs:element name="utr">

<xs:annotation>

<xs:documentation>

Root element of the XBRL Data Type Registry

</xs:documentation>

</xs:annotation>

<xs:complexType>

<xs:sequence>

<xs:element name="units">

<xs:complexType>

<xs:sequence minOccurs="0" maxOccurs="unbounded">

<xs:element name="unit">

<xs:complexType>

<xs:group ref="utr:unitGroup"/>

<xs:attribute name="id" type="xs:ID"/>

</xs:complexType>

</xs:element>

</xs:sequence>

</xs:complexType>

</xs:element>

</xs:sequence>

<xs:attribute name="version" type="xs:string" fixed="1.0"/>

</xs:complexType>

</xs:element>

<xs:element name="unitId">

<xs:annotation>

<xs:documentation>

The identifier to be used in the id attribute of the xs:unit declaration of instances. It will not be unique in the scope of the DTR because there could be (for example) a REC definition of a unit, and an IWD version of it.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:string">

<xs:pattern value="(\{numerator\})?[^\{\}]+(\{denominator\})?[^\{\}]*"/>

</xs:restriction>

</xs:simpleType>

</xs:element>

<xs:element name="unitName">

<xs:annotation>

<xs:documentation>

The name of the unit being defined, which may have spaces and other characters and is conventionally in Proper Case.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:string">

<xs:pattern value="(\{numerator\})?[^\{\}]+(\{denominator\})?[^\{\}]*"/>

</xs:restriction>

</xs:simpleType>

</xs:element>

<xs:element name="nsUnit">

<xs:annotation>

<xs:documentation>

The namespace in which the unit is declared in a xbrli:measure element. If absent, it means that the unit is not a simple measure.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:anyURI"/>

</xs:simpleType>

</xs:element>

<xs:element name="itemType">

<xs:annotation>

<xs:documentation>

The local-name of a type with which this unit may be used.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:NCName"/>

</xs:simpleType>

</xs:element>

<xs:element name="nsItemType">

<xs:annotation>

<xs:documentation>

Item type namespace; absent if the namespace does not matter.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:anyURI"/>

</xs:simpleType>

</xs:element>

<xs:element name="itemTypeDate" type="xs:date">

<xs:annotation>

<xs:documentation>

Version date of the XBRL specification or data type registry in which the item type first appears, or empty if the type is not (yet) present.

</xs:documentation>

</xs:annotation>

</xs:element>

<xs:element name="symbol">

<xs:annotation>

<xs:documentation>

The symbol used when rendering figures measured in the unit. This may be unicode such as a currency symbol. Monetary symbols are conventionally displayed before a number; other symbols conventionally displayed after.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:string"/>

</xs:simpleType>

</xs:element>

<xs:element name="definition" type="utr:DocumentationType">

<xs:annotation>

<xs:documentation>

The meaning of the unit, in English.

</xs:documentation>

</xs:annotation>

</xs:element>

<xs:element name="baseStandard">

<xs:annotation>

<xs:documentation>

A token indicating the authority or source of the unit definition: Customary, ISO4217, Non-SI, SI, XBRL.

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:string">

<xs:enumeration value="ISO4217"/>

<xs:enumeration value="SI"/>

<xs:enumeration value="Customary"/>

<xs:enumeration value="Non-SI"/>

<xs:enumeration value="XBRL"/>

<xs:enumeration value=""/>

</xs:restriction>

</xs:simpleType>

</xs:element>

<xs:complexType name="mathExpression">

<xs:sequence>

<xs:element
xmlns:math="http://www.w3.org/1998/Math/MathML" ref="math:math"/>

</xs:sequence>

</xs:complexType>

<xs:element name="conversionPresentation" type="utr:mathExpression"/>

<xs:element name="conversionContent" type="utr:mathExpression"/>

<xs:element name="status">

<xs:annotation>

<xs:documentation>

The XBRL International status of this unit: CR, PWD, REC, NIE, PROPOSED, IWD, ACK, RR

</xs:documentation>

</xs:annotation>

<xs:simpleType>

<xs:restriction base="xs:token">

<xs:enumeration value="PWD">

<xs:annotation>

<xs:documentation>

Public Working Draft

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="CR">

<xs:annotation>

<xs:documentation>

Candidate Recommendation

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="REC">

<xs:annotation>

<xs:documentation>

Recommendation

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="NIE">

<xs:annotation>

<xs:documentation>

Not In Effect

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="PROPOSED">

<xs:annotation>

<xs:documentation>

Proposed

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="IWD">

<xs:annotation>

<xs:documentation>

Internal Working Draft

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="ACK">

<xs:annotation>

<xs:documentation>

Acknowledged

</xs:documentation>

</xs:annotation>

</xs:enumeration>

<xs:enumeration value="RR">

<xs:annotation>

<xs:documentation>

Rescinded Recommendation

</xs:documentation>

</xs:annotation>

</xs:enumeration>

</xs:restriction>

</xs:simpleType>

</xs:element>

<xs:element name="versionDate" type="xs:date">

<xs:annotation>

<xs:documentation>

Effective date of this version of the unit; all versions of the same uhit with earlier dates are superseded

</xs:documentation>

</xs:annotation>

</xs:element>

</xs:schema>

Appendix B Sample utr document (non-normative)

The following is an example of a utr (as defined by the schema in Appendix A above). It contains only a single entry to illustrate the definition of a unit.


      <?xml version="1.0" encoding="UTF-8"?>

<units>

TND

</unitId>

Tunisian dinar

</unitName>

http://www.xbrl.org/2003/iso4217

</nsUnit>

monetaryItemType

</itemType>

http://www.xbrl.org/2003/instance

</nsItemType>

2003-12-31

</itemTypeDate>

Tunisian dinar

</definition>

ISO4217

</baseStandard>

IWD

</status>

2010-10-31

</versionDate>

</unit>

</units>

</utr>

Appendix C References

IETF RFC 2119: IETF (Internet Engineering Task Force). "RFC 2119: Key words for use in RFCs to Indicate Requirement Levels"
Scott Bradner.
(See http://www.ietf.org/rfc/rfc2119.txt)
ISO: International Standards Organisation. " ISO 4217 Currency codes, ISO 639 Language codes, ISO 3166 Country codes, ISO 8601 international standard numeric date and time representations. "
(See http://www.iso.ch/)
UTR PROCESS: XBRL International Inc.. "Units Registry - Process 1.0"
Hugh Wallis, and Walter Hamscher.
(See http://www.xbrl.org/Specification/utr/PWD-2011-05-05/utr-process-PWD-2011-05-05.html)
XBRL 2.1: XBRL International Inc.. "Extensible Business Reporting Language (XBRL) 2.1 Includes Corrected Errata Up To 2008-07-02"
Phillip Engel, Walter Hamscher, Geoff Shuetrim, David vun Kannon, and Hugh Wallis.
(See http://www.xbrl.org/Specification/XBRL-RECOMMENDATION-2003-12-31+Corrected-Errata-2008-07-02.htm)

Appendix D Intellectual property status (non-normative)

This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to XBRL International or XBRL organizations, except as required to translate it into languages other than English. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).

This document and the information contained herein is provided on an "AS IS" basis and XBRL INTERNATIONAL DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

The attention of users of this document is directed to the possibility that compliance with or adoption of XBRL International specifications may require use of an invention covered by patent rights. XBRL International shall not be responsible for identifying patents for which a license may be required by any XBRL International specification, or for conducting legal inquiries into the legal validity or scope of those patents that are brought to its attention. XBRL International specifications are prospective and advisory only. Prospective users are responsible for protecting themselves against liability for infringement of patents. XBRL International takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).

Appendix E Acknowledgements (non-normative)

This document could not have been written without the contributions of many people.

Appendix F Document history (non-normative)

Date	Author	Details
23 March 2011	Walter Hamscher	Initial version based on DTR.
17 April 2011	Walter Hamscher	Updated the structure declaration to match the current UTR implementation.
05 May 2011	Hugh Wallis	Editorial for publication as PWD.

Appendix G Errata corrections in this document

This appendix contains a list of the errata that have been incorporated into this document. This represents all those errata corrections that have been approved by the XBRL International Link Role Registry Approval Manager up to and including 05 May 2011. Hyperlinks to relevant e-mail threads may only be followed by those who have access to the relevant mailing lists. Access to internal XBRL mailing lists is restricted to members of XBRL International Inc.

No errata have been incorporated into this document.

Units Registry - Structure 1.0

Public Working Draft 05 May 2011

Status

Abstract

Table of Contents

Appendices

Table

Examples

Definitions

1 Goals

1.1 Relationship to other work

1.2 Terminology

1.3 Language

1.4 Document conventions

1.4.1 Typographic conventions

1.4.1.1 Definition notation

1.4.1.2 Footnote notation

1.4.1.3 Element and attribute notation

1.4.2 Formatting conventions

2 Data Model

3 Hosting on the XBRL.org website

4 Status of Units in the UTR and Implications for Software

Appendix A Schema

A.1 utr.xsd

Appendix B Sample utr document (non-normative)

Appendix C References

Appendix D Intellectual property status (non-normative)

Appendix E Acknowledgements (non-normative)

Appendix F Document history (non-normative)

Appendix G Errata corrections in this document