Consolidated Statements of Stockholders’ Equity (USD $) In Thousands	Total	Common Class A2 [Member]	Preferred Stock	Unrestricted Common Stock [Member]	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Beginning of Period at Dec. 31, 2010	$ 175,874	$ 383	$ 0	$ 518	$ 42,858	$ 133,087	$ 0	$ (972)
Conversion of Stock, Amount Converted	0	(383)		383
Dividends, Common Stock, Cash	(40,372)					(40,372)
Share-based Compensation	12,618				12,618
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0			7	(7)
Excess Tax Benefit from Share-based Compensation, Financing Activities	0
Treasury Stock, Value, Acquired, Cost Method	(51,329)						(51,329)
Net income	139,406					139,406
Post-retirement benefit obligation adjustments- net of tax expense	73							73
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest End of Period at Dec. 31, 2011	236,270	0	0	908	55,469	232,121	(51,329)	(899)
Dividends, Common Stock, Cash	(114,025)					(114,025)
Share-based Compensation	12,348				12,348
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0			5	(5)
Excess Tax Benefit from Share-based Compensation, Financing Activities	0
Treasury Stock, Value, Acquired, Cost Method	(52,872)						(52,872)
Net income	157,395
Post-retirement benefit obligation adjustments- net of tax expense	6							6
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest End of Period at Dec. 31, 2012	239,122	0	0	913	67,812	275,491	(104,201)	(893)
Dividends, Common Stock, Cash	(102,200)					(102,200)
Share-based Compensation	20,823				20,823
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	0			6	(6)
Excess Tax Benefit from Share-based Compensation, Financing Activities	2,356
Treasury Stock, Value, Acquired, Cost Method	(51,426)						(51,426)
Net income	175,999
Post-retirement benefit obligation adjustments- net of tax expense	(157)							157
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest End of Period at Dec. 31, 2013	$ 284,517	$ 0	$ 0	$ 919	$ 90,985	$ 349,290	$ (155,627)	$ (1,050)