Parents

All good children know their parents. Parents are not explicitly defined in an XBRL taxonomy. In some sense a parent is a reverse arc. As well as being able to know where a node is used, it is used to ensure that any arc attributes applied to a node are applied to the correct relationship. The same label may be used as the 'to' label in more than one arc. This makes the attributes of the node itself ambiguous because of an implementation issue. For performance reasons, it is desirable that nodes added to a nodes array by reference.

However, this means that any change to one instance of a node changes them all (because they really one and the same node). By the time the hierarchy has been created and persisted this issue goes away because the nodes are replicated. However, while the arcs are being analyzed is it’s a real issue.