Statement of Shareholders' Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Common Stock, Shares, Outstanding at Dec. 31, 2012		47,899,584				1,550,173
Common Stock, Value, Issued at Dec. 31, 2012	$ 187,913,000	$ 1,233,000	$ 0	$ 361,255,000	$ (8,413,000)	$ (171,845,000)	$ 5,683,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Value, Stock Options Exercised	83,000	$ 0	(1,411,000)	0	0	$ 1,494,000	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period						(12,000)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(222,176)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	20,526,000	$ 0	1,047,000	(5,509,000)	0	$ 24,988,000	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	3,744,000	0	3,744,000	0	0	0	0
Stock Repurchased During Period, Value	(227,216,000)	$ 0	0	0	0	$ (227,216,000)	0
Stock Repurchased During Period, Shares		0				1,482,198
Dividends	(58,642,000)	$ 0	0	(58,642,000)	0	$ 0	0
Treasury Stock, Retired, Cost Method, Amount	0	$ (30,000)	(3,380,000)	(123,985,000)	0	$ 127,395,000	0
Treasury Stock, Shares, Retired		(1,149,582)				(1,149,582)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Net of Tax	213,000	$ 0	0	0	(213,000)	$ 0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	243,194,000	0	0	242,811,000	0	0
Net Income (Loss) Attributable to Noncontrolling Interest	383,000						383,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	242,981,000
Common Stock, Value, Issued Period End at Dec. 31, 2013	169,389,000	$ 1,203,000	0	415,930,000	(8,626,000)	$ (245,184,000)	6,066,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2013		46,750,002				1,648,613
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(216,395)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	20,470,000	$ 0	1,295,000	(12,683,000)	0	$ 31,858,000	0
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	3,020,000	0	3,020,000	0	0	0	0
Stock Repurchased During Period, Value	(264,368,000)	$ 0	0	0	0	$ (264,368,000)	0
Stock Repurchased During Period, Shares		0				1,680,800
Dividends	(89,089,000)	$ 0	0	(89,089,000)	0	$ 0	0
Treasury Stock, Retired, Cost Method, Amount	0	$ (29,000)	(4,315,000)	(155,737,000)	0	$ 160,081,000	0
Treasury Stock, Shares, Retired		(1,150,000)				(1,150,000)
Stockholders' Equity, Other	(787,000)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders		$ 0	0	0	0	$ 0	787,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Net of Tax	3,268,000	0	0	0	(3,268,000)	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	258,626,000	0	0	257,485,000	0	0
Net Income (Loss) Attributable to Noncontrolling Interest	1,141,000						1,141,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	255,358,000
Common Stock, Value, Issued Period End at Dec. 31, 2014	$ 93,993,000	$ 1,174,000	0	415,906,000	(11,894,000)	$ (317,613,000)	6,420,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2014	43,636,984	45,600,002				1,963,018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		0				(183,455)
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	$ 21,279,000	$ 0	3,267,000	(11,044,000)	0	$ 29,056,000	0
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	(175,000)	0	(175,000)	0	0	0	0
Stock Repurchased During Period, Value	(159,709,000)	$ 0	0	0	0	$ (159,709,000)	0
Stock Repurchased During Period, Shares		0				1,444,534
Dividends	(94,235,000)	$ 0	0	(94,235,000)	0	$ 0	0
Treasury Stock, Retired, Cost Method, Amount	$ 0	$ (32,000)	(3,092,000)	(206,267,000)	0	$ 209,391,000	0
Treasury Stock, Shares, Retired	1,250,000	(1,250,000)				(1,250,000)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	$ (1,140,000)	$ 0	0	0	0	$ 0	(1,140,000)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract]
Other Comprehensive Income (Loss), Net of Tax	(1,356,000)	0	0	0	1,356,000	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	114,932,000	0	0	114,847,000	0	0
Net Income (Loss) Attributable to Noncontrolling Interest	85,000						85,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	116,288,000
Common Stock, Value, Issued Period End at Dec. 31, 2015	$ (23,699,000)	$ 1,142,000	$ 0	$ 219,207,000	$ (10,538,000)	$ (238,875,000)	$ 5,365,000
Common Stock, Shares, Outstanding Period End at Dec. 31, 2015	42,375,905	44,350,002				1,974,097