In December 2008, the SEC approved final rules which require mpanies to submit financial statements in XBRL format with their SEC filings, beginning with quarterly June 2009 filings for the largest mpanies and within three years for all public mpanies. Previously, the SEC established a voluntary filing program for XBRL reporting in March 2005. Acrdingly, the objectives of our study are: (1) to provide an overview of the benefits and global development of XBRL and (2) to evaluate the extent of XBRL adoption following the implementation of the voluntary filing program. We find the quantity of voluntary reporting to be relatively low, but reporting significantly increased over time. Voluntary adopters are larger and more innovative firms in their industries. We find evidence suggesting increasing efficiency in XBRL reporting, as reporting lags have significantly decreased over time. This efficiency improvement is positive news and may arue to other mpanies after they are required to use XBRL reporting. XBRL is expected to have a positive effect on acunting and financial reporting worldwide, particularly used in njunction with International Financial Reporting Standards (IFRS).