What is a dimension?

XBRL filings use a multi-dimensional structure. Information can be tagged as non-dimensional (belonging to the entire company), or can be assigned dimensional ‘members’, which describe it as belonging to a subset of the company. For example, a company might report Assets for their whole company of $1 billion. But they might also report Assets for their North America segment of $800 million. They likely will do this by using the same Assets tag, but adding to it a dimensional member, like NorthAmericaMember.