Condensed Consolidated Statements of Equity (Unaudited) (USD $) In Thousands	Total	Common Stock Voting Shares Issued	Common Stock Non-Voting Shares Issued	Paid-In Capital	Retained Earnings/ (Accumulated Deficit)	Accumulated Other Comprehensive Loss	Noncontrolling Interest
Balance at Dec. 31, 2009	$ 431,991	$ 204	$ 95	$ 1,013,790	$ (519,220)	$ (62,878)	$ 0
Balance, shares at Dec. 31, 2009		20,391	9,506
Net income	487,341				486,846		495
Other comprehensive loss	(32,995)					(32,995)
Comprehensive income	454,346
Exercise of stock options	13,995	5		13,990
Exercise of stock options, shares		547
Shares surrendered to fund withholding taxes	(2,477)			(2,477)
Shares surrendered to fund withholding taxes, shares		(13)
Tax benefit associated with exercise of stock options	412			412
Stock based compensation	2,548			2,548
Contribution by noncontrolling interest	134						134
Balance at Dec. 31, 2010	900,949	209	95	1,028,263	(32,374)	(95,873)	629
Balance, shares at Dec. 31, 2010		20,925	9,506
Net income	20,123				19,784		339
Other comprehensive loss	(816)					(816)
Comprehensive income	19,307
Exercise of stock options	448	3		445
Exercise of stock options, shares		281
Shares surrendered to fund withholding taxes	(16,905)			(16,905)
Tax benefit associated with exercise of stock options	1,095			1,095
Stock based compensation	867			867
Balance at Sep. 30, 2011	$ 905,761	$ 212	$ 95	$ 1,013,765	$ (12,590)	$ (96,689)	$ 968
Balance, shares at Sep. 30, 2011		21,206	9,506