CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Total
Balance at Dec. 31, 2009	$ 48,539	$ 1,012,983	$ 260,121	$ (33,217)	$ 1,288,426
Net income	0	0	103,500	0	103,500
Other comprehensive income:
Other comprehensive loss				(2,823)	(2,823)
Total comprehensive income					100,677
Common stock purchased under share repurchase program	(2,165)	(37,226)	0	0	(39,391)
Common stock dividend declared ($1.00 per share)	0	0	(47,090)	0	(47,090)
Tax effect of stock-based compensation	0	(2,055)	0	0	(2,055)
Stock-based compensation expense	0	12,752	0	0	12,752
Issuance of common stock, net	716	(1,041)	0	0	(325)
Balance at Dec. 31, 2010	47,090	985,413	316,531	(36,040)	1,312,994
Net income	0	0	86,148	0	86,148
Other comprehensive income:
Other comprehensive loss				(7,575)	(7,575)
Total comprehensive income					78,573
Tax effect of stock-based compensation	0	(367)	0	0	(367)
Stock-based compensation expense	0	8,818	0	0	8,818
Issuance of common stock, net	239	(430)	0	0	(191)
Balance at Dec. 31, 2011	47,329	993,434	402,679	(43,615)	1,399,827
Net income	0	0	(265,400)	0	(265,400)
Other comprehensive income:
Other comprehensive loss				41	41
Total comprehensive income					(265,359)
Tax effect of stock-based compensation	0	(195)	0	0	(195)
Stock-based compensation expense	0	9,470	0	0	9,470
Issuance of common stock, net	227	(106)	0	0	121
Balance at Dec. 31, 2012	$ 47,556	$ 1,002,603	$ 137,279	$ (43,574)	$ 1,143,864