9. A method of performing XBRL taxonomy migration comprising: receiving an XBRL document having XBRL tags of a first version of a first XBRL taxonomy; migrating, by a processor, the received XBRL document to a second version of the first XBRL taxonomy by replacing XBRL concepts of the first version of the first XBRL taxonomy in the received XBRL document with XBRL concepts of the second version of the first XBRL taxonomy such that the migrated XBRL document no longer uses the first version of the first XBRL taxonomy, each of the first version of the first XBRL taxonomy and the second version of the first XBRL taxonomy including a base taxonomy and optionally one or more extensions of the base taxonomy, wherein the migrating includes maintaining tags from the received XBRL document that are of a second XBRL taxonomy in the migrated XBRL document, the second XBRL taxonomy being different from the first XBRL taxonomy and tags of the second XBRL taxonomy being simultaneously included with the XBRL tags of the first XBRL taxonomy in the received XBRL document.
24. The method of claim 9 , wherein the migrating comprises a many-to-one mapping in which a plurality of deprecated XBRL concepts of the first version of the first XBRL taxonomy are mapped to a single XBRL concept of the second version of the first XBRL taxonomy, the single XBRL concept of the second version aggregating the plurality of deprecated XBRL concepts of the first version which have greater specificity than the single XBRL concept of the second version.