Statement of Shareholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Common Stock, Value, Issued at Dec. 31, 2008	$ 188,285,000	$ 1,430,000	$ 53,019,000	$ 382,266,000	$ (4,927,000)	$ (245,661,000)	$ 2,158,000
Common Stock, Shares, Outstanding at Dec. 31, 2008		51,039,912				4,999,846
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Stock Options Exercised	408,000	0	(1,767,000)	0	0	2,175,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period						(55,300)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(156,300)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	5,896,000	0	(280,000)	0	0	6,176,000	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	170,000	0	170,000	0	0	0	0
Stock Repurchased During Period, Value	(9,389,000)	0	0	0	0	(9,389,000)	0
Stock Repurchased During Period, Shares		0				278,258
Dividends	(26,416,000)	0	0	(26,416,000)	0	0	0
Settlement of Warrants	0
Sales Of Note Hedge Claim	10,577,000	0	10,577,000	0	0	0	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(259,000)	0	0	0	0	0	(259,000)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(1,845,000)	0	0	0	(1,845,000)	0	0
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax	236,000	0	0	0	236,000	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	114,095,000	0	0	113,604,000	0	0	491,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	112,486,000
Common Stock, Value, Issued Period End at Dec. 31, 2009	281,758,000	1,430,000	61,719,000	469,454,000	(6,536,000)	(246,699,000)	2,390,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2009		51,039,912				5,066,504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Stock Options Exercised	346,000	0	(1,537,000)	0	0	1,883,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period						(46,230)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(186,198)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	8,517,000	0	1,424,000	(575,000)	0	7,668,000	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	967,000	0	967,000	0	0	0	0
Stock Repurchased During Period, Value	(92,487,000)	0	0	0	0	(92,487,000)	0
Stock Repurchased During Period, Shares		0				1,493,017
Dividends	(39,791,000)	0	0	(39,791,000)	0	0	0
Treasury Stock, Retired, Cost Method, Amount	0	(33,000)	(33,744,000)	(17,733,000)	0	51,510,000	0
Treasury Stock, Shares, Retired		(1,300,000)				(1,300,000)
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	(8,864,000)	0	(8,864,000)	0	0	0	0
Stock Issued During Period, Shares, Conversion of Convertible Securities		0				(808,367)
Stock Issued During Period, Value, Conversion of Convertible Securities	(3,811,000)	0	(19,965,000)	(19,281,000)	0	35,435,000	0
Settlement of Warrants	0
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	156,000	0	0	0	0	0	156,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(181,000)	0	0	0	0	0	(181,000)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(13,000)	0	0	0	(13,000)	0	0
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax	342,000	0	0	0	342,000	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	145,401,000	0	0	144,917,000	0	0	484,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	145,730,000
Common Stock, Value, Issued Period End at Dec. 31, 2010	292,340,000	1,397,000	0	536,991,000	(6,207,000)	(242,690,000)	2,849,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2010	45,521,186	49,739,912				4,218,726
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Stock Options Exercised	297,000	0	(1,672,000)	0	0	1,969,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(42,400)					(42,400)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(177,271)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	17,165,000	0	9,588,000	(1,992,000)	0	9,569,000	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	2,559,000	0	2,559,000	0	0	0	0
Stock Repurchased During Period, Value	(61,825,000)	0	0	0	0	(61,825,000)	0
Stock Repurchased During Period, Shares		0				669,649
Dividends	(46,027,000)	0	0	(46,027,000)	0	0	0
Treasury Stock, Retired, Cost Method, Amount	0	(21,000)	0	(40,894,000)	0	40,915,000	0
Treasury Stock, Shares, Retired	702,106	(702,106)				(702,106)
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	8,864,000	0	8,864,000	0	0	0	0
Stock Issued During Period, Shares, Conversion of Convertible Securities		0				(1,851,869)
Stock Issued During Period, Value, Conversion of Convertible Securities	(2,322,000)	0	(13,603,000)	(90,192,000)	0	101,473,000	0
Settlement of Warrants	(219,451,000)	0	3,724,000	258,910,000	0	(43,183,000)	0
Settlement of Warrants, Shares		0				(706,395)
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	1,194,000	0	0	0	0	0	1,194,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(251,000)	0	0	0	0	0	(251,000)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	4,165,000	0	0	0	4,165,000	0	0
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Recognized in Net Periodic Pension Cost, Net of Tax	303,000	0	0	0	303,000	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	184,644,000	0	0	184,684,000	0	0	(40,000)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	189,112,000
Common Stock, Value, Issued Period End at Dec. 31, 2011	$ 181,655,000	$ 1,376,000	$ 2,012,000	$ 283,660,000	$ (1,739,000)	$ (107,406,000)	$ 3,752,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2011	47,629,472	49,037,806				1,408,334