Exclude sections from untagged highlighting

[austinmatherne-wk]

What should we change and why?

The highlight feature for untagged content in review mode is useful, though it often flags content that shouldn't be tagged—like document page numbers or sections of the document which are excluded from XBRL tagging requirements.

Creating an algorithm to automatically decide what to skip might not play nice with all taxonomies and document formats the viewer needs to support. Instead, reports could use CSS class names prefixed with -ixh-, like suggested in this XBRL international working group note to signal viewers to ignore certain content.

While generating the iXBRL report, a class like -ixh-ignore-untagged could be applied to footers or multi-page document parts to indicate areas where untagged number highlighting isn't needed.

@paulwarren-wk, as you were the editor of that WGN, I'm particularly keen to hear your thoughts.

[paulwarren-wk]

I think it's a good idea, although I'm not sure that -ixh- is the right place for it. The WGN suggests that is only to be used for things that are defined by XII, and I'm not sure if the "finding untagged numbers" is sufficiently generic functionality that we'd want to standardise it at that level.

Instead, what I think we actually want is the ability to have vendor-specific prefixes, e.g. -arelle-. There's nothing stopping us doing that at the moment, although it might be worth updating the WGN to explicitly endorse the approach of using vendor-specific class prefixes.