Tagging Numeric Facts with Units

All XBRL numeric facts must be tagged with a unit of measure. One of XBRL’s primary purposes is to provide a machine readable representation of your financial report that is faithful to the meaning of the original value. Tagging numeric facts with units eliminates ambiguity when your XBRL documents are interpreted by software applications.

Understanding Units

It is required to report each numeric fact value with a unit that is consistent with the item type of the fact’s XBRL concept. Here are some tips to expand on this requirement:

  • All XBRL concepts are defined to represent a particular item type or data type. An item type can be something like monetary, percent, boolean, etc.
  • All XBRL numeric facts are assigned a unit of measure. For example, a fact value of 149 with GBP as the unit of measure communicates £149.
  • Each item type can be assigned only a subset of all possible units of measure. In other words, the item type determines which units you can use.

Commonly Used Units

When deciding on a unit, you must take into account the item type of the concept, and then use or create an appropriate unit.

If you select one of these standard units in Wdesk, the “iso” prefix is added automatically, meaning that this value is defined in the XBRL Units Registry. If you create custom units, Wdesk inserts your company’s XBRL Namespace Prefix. This item is set at the account level by your Wdesk account administrator.