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, 2009	$ 281,758,000	$ 1,316,000	$ 61,833,000	$ 469,454,000	$ (6,536,000)	$ (246,699,000)	$ 2,390,000
Common Stock, Shares, Outstanding 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	329,000	0	0	0	(329,000)	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	145,401,000	0	0	144,917,000	0	0
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	1,283,000	114,000	536,991,000	(6,207,000)	(242,690,000)	2,849,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2010		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)
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)
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	4,468,000	0	0	0	(4,468,000)	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	184,644,000	0	0	184,684,000	0	0
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	1,262,000	2,126,000	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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Stock Options Exercised	5,000	0	(60,000)	0	0	65,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(1,042)					(1,042)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(299,964)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	18,381,000	0	276,000	(6,530,000)	0	24,635,000	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	5,226,000	0	5,226,000	0	0	0	0
Stock Repurchased During Period, Value	(175,732,000)	0	0	0	0	(175,732,000)	0
Stock Repurchased During Period, Shares		0				1,581,069
Dividends	(52,950,000)	0	0	(52,950,000)	0	0	0
Treasury Stock, Retired, Cost Method, Amount	0	(29,000)	(7,568,000)	(78,996,000)	0	86,593,000	0
Treasury Stock, Shares, Retired	1,138,224	(1,138,224)				(1,138,224)
Settlement of Warrants	0
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(110,000)	0	0	0	0	0	(110,000)
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	1,800,000	0	0	0	0	0	1,800,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(300,000)	0	0	0	0	0	(300,000)
Stockholders' Equity, Other Shares		2				0
Stockholders' Equity, Other	0	0	0	0	0	0	0
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, Portion Attributable to Parent	6,674,000	0	0	0	(6,674,000)	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	216,612,000	0	0	216,071,000	0	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	209,938,000
Common Stock, Value, Issued Period End at Dec. 31, 2012	$ 187,913,000	$ 1,233,000	$ 0	$ 361,255,000	$ (8,413,000)	$ (171,845,000)	$ 5,683,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2012	46,349,411	47,899,584				1,550,173