CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Trade accounts receivable, allowance for doubtful accounts	$ 1,568	$ 2,709
Common stock, par value	$ 0.01	$ 0.01
Common stock, issued	89,484	88,841
Common stock, outstanding	89,484	88,841