Consolidated Statement 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, 2013	$ 687,342	$ 997	$ 267,406	$ 850,600	$ (415,802)	$ (15,859)
Balance (in shares) at Dec. 31, 2013		99,701
Increase (Decrease) in Stockholders' Equity
Net income	157,852			157,852
Recognition of equity compensation	27,679		27,679
Net issuance/forfeiture of nonvested shares			(12,883)		12,883
Dividends accrued, $0.68 per share	(57,792)			(57,792)
Excess tax benefits from share-based payment arrangements	16,861		16,861
Repurchase of common stock	(61,722)				(61,722)
Other comprehensive loss	2,103					2,103
Balance at Jun. 30, 2014	$ 772,323	$ 997	$ 299,063	$ 950,660	$ (464,641)	$ (13,756)
Balance (in shares) at Jun. 30, 2014		99,701