The answer is very simple. XBRL was first conceived by an Auditor (Charlie Hoffman CPA) and pushed in the first years by AICPA (American Institute of Certified Public Accountants). This is the reason why, since the beginning, the most important auditing firms (the big four) has been involved in the development. XBRL importance can be appreciated by different points of view:
From the functional perspective
XBRL would allow auditing firms to collect information about their clients using the same technology by using a common standard (XBRL). All corporate organizations would have the possibility to “Export” data to XBRL. Tax Agencies also shares this goal. Since Tax Agencies require to have access to the same information when supervising companies, they need companies to produce finantial information using a common standard.
From the practical point of view
XBRL allows auditing firms to create strong relationships and get better knowledge about what really happens inside a company. The use of XBRL facilitates the function of creating the auditing report.
The relation between Reporting Standard and the use of XBRL standard for auditing
In the future, XBRL could be used as the standard for implementing Continuous Auditing. From Reporting Standard we have been several years preparing several companies to aggregate XBRL reporting to their systems. In this way, we are making our small contribution to the development and implementation of XBRL standard.