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The XBRL Taxonomy Packages specification defines a standard for distributing XBRL taxonomies within ZIP files. The specification was originally intended to be used only for the distribution of taxonomies, and not for iXBRL and XBRL reports (instance documents), but it is now recognised that this may be a useful application of the specification. This Working Group Note addresses some of the issues around doing this, and suggests a preferred approach for how XBRL and iXBRL reports should be included within taxonomy packages.
The XBRL Taxonomy Packages specification [Taxonomy Package] defines a standard way for distributing an XBRL taxonomy as a ZIP file, with additional metadata that can ease the automated consumption of the taxonomy. This metadata includes:
The specification neither endorses nor prohibits the inclusion of files other than XBRL taxonomy files within the package. In reporting environments where preparers may provide an extension taxonomy to support an XBRL [XBRL 2.1] or iXBRL [Inline XBRL Specification] report, a similar packaging issue may arise, as the report will contain references to the report which need to be resolved to files within the extension taxonomy. This can be by relative references, in which case it is important to preserve the relative locations of the report and its taxonomy, or absolute references, in which case it is convenient to be able to re-map them to a local copy of the taxonomy.
The Specification Working Group opted to exclude explicit support for XBRL or iXBRL reports from the Taxonomy Packages specification for a number of reasons. One of these was a desire to avoid reinforcing the notion that reports and extension taxonomies should be published as part of the same publication cycle. Reports are typically prepared on a regular basis (e.g. monthly, quarterly or annually) and contain the data being reported. The taxonomy, including any extension taxonomy, defines the structure of the report, and need not necessarily change from one reporting period to the next.
Comparability of reports is improved if there is consistency of the report structure between subsequent reports, and so there is an argument that extension taxonomies should be published separately from the report, and only updated if a change is needed to the report structure.
The Working Group recognises that the infrastructure required to support separation of extension taxonomies from XBRL and iXBRL reports adds complexity to a filing system, and that combining the XBRL report and extension taxonomy into a single package can simplify the task of maintaining references from the report to the taxonomy.
In order to allow software to automatically locate XBRL and iXBRL reports contained within a taxonomy package, this note defines a convention for their location and naming.
The Taxonomy Packages specification requires that the package contains a single,
top-level directory named consistently with the ZIP file itself. This note
recommends that XBRL and iXBRL reports are placed within a subdirectory of this top-level
reports. Taxonomy files may be placed in any
other directory. It is common practice to place taxonomy files within a directory
structure that reflects the absolute URL from which they are remapped, with the
first level of the structure reflecting the hostname part of the URL.
The example below shows the file structure for a taxonomy package containing a report (
myreport.html) and a taxonomy.
XBRL reports should have a
.xbrl extension, and iXBRL (Inline
XBRL) reports should have a
.xbrl files within the
will be considered to be separate reports.
.html files within a subdirectory of the
reports directory will be treated as a single Inline XBRL
Multiple Inline XBRL Document Sets can be provided by including multiple subdirectories of the
.xbrl files should not be placed within subdirectories of the
In order to avoid the possibility of providing conflicting or inconsistent data, if the package includes an iXBRL report, it should not also include a copy of the XBRL data which can be extracted from it. Consumers of the iXBRL report can perform this extraction using standard software, if required.
Taxonomy packages provide a mechanism for remapping absolute, public URLs to files within the package. This can be used to give the taxonomy files within the package an absolute URL, even if they are not actually published at that location. This URL can then be used to reference the taxonomy from the report.
In the example above, the
catalog.xml file could include a
This will remap all URLs starting with
https://xbrl.example.com/v1/ to the corresponding location within
This allows the XBRL report
to include a taxonomy reference (using the
to the absolute URL:
which will be resolved to the
taxonomy.xsd file within the
Absolute URLs, resolved via remappings, as shown in the example above, are the preferred way to reference an extension taxonomy from an XBRL or iXBRL report included within a taxonomy package, and should be used if the taxonomy package provides remappings for the taxonomy.
If the package does not provide remappings then it is acceptable to use a relative reference from the report to the taxonomy files.
The taxonomy file or files referenced by the report should match an entry point
defined in the taxonomy package metadata. If the entry point includes multiple
entry point documents then the report should include references to all of them (using
<xbrli:linkbaseRef> elements). It should be noted that use of
<xbrli:linkbaseRef> is discouraged, and is not expected to be supported by future drafts of the XBRL Open Information Model specification [OIM].
Remapped URLs for taxonomy files within the package should be unique, and should not be redefined in other packages. This can be achieved by:
acme.tld, the host part of the URL could be
The remapped prefix should include the version identifier.
XBRL and iXBRL reports must not be included as entry points in the
taxonomyPackage.xml file. The Taxonomy Packages specification [Taxonomy Package] requires that entry points include only taxonomy schema or linkbase files.
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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 Base Specification and Maintenance Working Group up to and including 14 August 2018. 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.