Negative values have been another source of confusion. Some values that appear as negative on traditional financial statements generally should not in XBRL. "One of the most common errors filers make is to incorrectly enter an amount with a negative value," states.

Still, some companies seem to be doing it right. One key to success: Start early. Atlas Air Worldwide, a provider of aircraft and aviation services based in Purchase, N.Y., is part of the next group of XBRL filers, says CFO Spencer Schwartz. The company began its efforts a year ago, analyzing whether to outsource the process or manage it in-house. "We decided it was more economical to bring it in-house," Schwartz says. While Atlas had to purchase and implement new software to aid in the conversion, it will have a lower cost for each filing. In addition, the solution links to the company's general ledger and other systems, automatically pulling information from them. "It's pretty easy to use."

In addition, employees challenged themselves as they were working with the financial statements. Every time they considered a specialty tag, they asked themselves if the line item in question wasn't already covered by the existing taxonomy, says Keith Mayer, vice president and corporate controller. "That discipline has really helped us."

When Atlas Air submitted a test XBRL file to the SEC, it received back no errors, Schwartz adds.