Consolidated Statements Of Equity (USD $) In Thousands	Voting Common Stock [Member]	Non-Voting Common Stock [Member]	Paid-In Capital [Member]	Treasury Stock Voting [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2008	$ 203	$ 95	$ 1,007,011		$ (750,922)	$ (46,730)		$ 209,657
Balance, shares at Dec. 31, 2008	20,287	9,506
Net income					231,702			231,702
Other comprehensive loss						(16,148)		(16,148)
Comprehensive income								215,554
Exercise of stock options	1		1,403					1,404
Exercise of stock options, shares	74
Shares surrendered to fund withholding taxes			(1,559)					(1,559)
Shares surrendered to fund withholding taxes, shares	(43)
Stock based compensation	0		6,935					6,935
Stock based compensation, shares	73
Balance at Dec. 31, 2009	204	95	1,013,790		(519,220)	(62,878)		431,991
Balance, shares at Dec. 31, 2009	20,391	9,506
Net income					486,846		495	487,341
Other comprehensive loss						(32,995)		(32,995)
Comprehensive income								454,346
Exercise of stock options	5		13,990					13,995
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	209	95	1,028,263		(32,374)	(95,873)	629	900,949
Balance, shares at Dec. 31, 2010	20,925	9,506
Net income					126,677		497	127,174
Other comprehensive loss						(58,602)		(58,602)
Comprehensive income								68,572
Exercise of stock options	3		1,055					1,058
Exercise of stock options, shares	305
Shares surrendered to fund withholding taxes			(16,972)					(16,972)
Tax benefit associated with exercise of stock options			1,198					1,198
Stock based compensation			1,180					1,180
Voting common stock repurchased, shares				136
Voting common stock repurchased				(8,400)				(8,400)
Balance at Dec. 31, 2011	$ 212	$ 95	$ 1,014,724	$ (8,400)	$ 94,303	$ (154,475)	$ 1,126	$ 947,585
Balance, shares at Dec. 31, 2011	21,230	9,506		136