CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2010	$ 457,161	$ 997	$ 201,442	$ 618,813	$ (346,064)	$ (18,027)
Balance (in shares) at Dec. 31, 2010		99,701
Increase (Decrease) in Stockholders' Equity
Net income	175,459			175,459
Recognition of equity compensation	46,473		46,457	16
Net issuance/forfeiture of nonvested shares			(40,442)		40,442
Dividends accrued, $1.18, $2.03 and $0.85 per share for the year ended 2013, 2012, and 2011 respectively	(73,007)			(73,007)
Exercise of stock options	5,080		949		4,131
Excess tax benefits from share-based payment arrangements	8,020		8,020
Repurchase of common stock	(65,463)				(65,463)
Other comprehensive income	(30,080)					(30,080)
Balance at Dec. 31, 2011	523,643	997	216,426	721,281	(366,954)	(48,107)
Balance (in shares) at Dec. 31, 2011		99,701
Increase (Decrease) in Stockholders' Equity
Net income	150,952			150,952
Recognition of equity compensation	49,993		49,937	56
Net issuance/forfeiture of nonvested shares			(43,106)		43,106
Dividends accrued, $1.18, $2.03 and $0.85 per share for the year ended 2013, 2012, and 2011 respectively	(173,866)			(173,866)
Exercise of stock options	105		(27)		132
Excess tax benefits from share-based payment arrangements	6,791		6,791
Repurchase of common stock	(48,688)				(48,688)
Other comprehensive income	1,310					1,310
Balance at Dec. 31, 2012	510,240	997	230,021	698,423	(372,404)	(46,797)
Balance (in shares) at Dec. 31, 2012		99,701
Increase (Decrease) in Stockholders' Equity
Net income	252,998			252,998
Recognition of equity compensation	53,179		52,992	187
Net issuance/forfeiture of nonvested shares			(28,564)		28,564
Dividends accrued, $1.18, $2.03 and $0.85 per share for the year ended 2013, 2012, and 2011 respectively	(101,008)			(101,008)
Exercise of stock options	135		(35)		170
Excess tax benefits from share-based payment arrangements	12,992		12,992
Repurchase of common stock	(72,132)				(72,132)
Other comprehensive income	30,938					30,938
Balance at Dec. 31, 2013	$ 687,342	$ 997	$ 267,406	$ 850,600	$ (415,802)	$ (15,859)
Balance (in shares) at Dec. 31, 2013		99,701