Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Accounts receivable, allowances for doubtful accounts	$ 594	$ 5,655
Common stock, par value (in dollars per share)	$ 0.25	$ 0.25
Common stock, shares authorized	180,000,000	180,000,000
Common stock, shares issued	110,834,088	110,834,088
Treasury stock, shares	2,799,118	2,603,324