Positive and Negative Fact Signs
Every numeric fact has a sign — either positive or negative. When you draft a document, a positive value is presumed unless you add characters to indicate a negative value. The two common examples of this include:
Preceding the number with a minus sign: -36,321
Putting it inside parentheses: (36,321)
Depending on the document context, sometimes you need to present a negative value as positive. Here are two examples of this:
"For the quarter ending June 30, 2012, we incurred an operating loss of $12.3 million."
|Operating Income (Loss)
In the former example, the numeric value is formatted as a positive number, and in the latter, as a negative number. To someone experienced in reading financial reports, these two examples mean the same thing. In XBRL, they would be reported as the same fact, where the sign of the fact reflects the natural balance of the XBRL concept used to tag the value. In other words, it would not reflect the document formatting.
Determining the Correct Sign
In the context of tagging XBRL facts, taking document formatting into account can lead to tagging the fact with the wrong sign. If you need to change the fact sign, see the Fact Sign article.
In the example above, the concept used is Operating Income (Loss). It has a balance type of credit, and its definition is "The net result for the period of deducting operating expenses from operating revenues."
As a concept that reports a net value, this can represent two interpretations, depending on the sign of the value. A positive value indicates a net operating income, and a negative value indicates a net operating loss. The sign of the XBRL fact value should reflect the intended meaning that you want to report. If you want to report a loss, the sign of the fact value must be negative.
The next example illustrates that a fact’s sign must reflect the balance type of the selected line item concept—again, not the sign used to reflect document formatting.
||Value as presented in document
||Sign presented in document
||Balance type of line item concept
||Change necessary to have fact reflect natural balance of the line item concept
|Accumulated impairment losses
||reverse to $29,502
XBRL Data Quality Validations Messages
When you generate an XBRL project in Wdesk, a data quality validations process is included. These validations provide additional quality assurance checks. One area of these tests focuses on identifying values that may incorrectly be reported as negative.
Two data quality validations messages identify a potentially false negative XBRL fact value:
Fact tagged with [CONCEPT NAME] was less than zero. This concept should not have a negative value unless it is being represented as a reported value associated with consolidations, eliminations or netting.
Fact tagged with [CONCEPT NAME] was less than zero. This concept does not follow a naming convention typically associated with facts having positive or negative values. While this might not be an error, we encourage reviewing the fact value for correct signage or review the extension for proper naming.
The first message, classified as an error, identifies negative facts tagged with a line item concept that would ordinarily never be negative. An example would be Accumulated Depreciation. The message also states that the most common exception to that rule is that the fact represents consolidations or eliminations.
The second message, classified as a warning, identifies negative facts tagged with a line item concept, where the SEC naming convention indicates that the value should not be negative.
NOTE: The information given here is meant to explain possible reasons that these messages are returned during the validation process. It is still up to you to investigate and correct any incorrect signs.