Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Condensed Consolidated Balance Sheets
Trade accounts receivable, allowances (in dollars)	$ 9,275	$ 21,692
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares	125,000	125,000
Common stock, issued shares	37,051	38,692
Common stock, outstanding shares	37,051	38,692