Consolidated Statement of Stockholders' Equity (USD $) In Thousands	Total	Regular Dividend	Special Dividend	Common Stock	Common Stock Special Dividend	Additional Paid-in Capital	Additional Paid-in Capital Special Dividend	(Accumulated Deficit) Retained Earnings	(Accumulated Deficit) Retained Earnings Regular Dividend	(Accumulated Deficit) Retained Earnings Special Dividend
Beginning Balance at Dec. 31, 2012	$ 1,521,620			$ 1,001		$ 1,146,488		$ 374,131
Beginning Balance (in shares) at Dec. 31, 2012				100,105
Net income	253,364							253,364
Issuance of common stock (in shares)				20
Issuance of common stock	20					20
Retirement of common stock (in shares)				(144)
Retirement of common stock	(5,454)			(1)		(5,453)
Dividend on common stock (in shares)					13,878
Dividend on common stock		(165,309)	(135,546)		139		542,541		(165,309)	(678,226)
Restricted stock compensation, net of forfeitures (in shares)				(23)
Restricted stock compensation, net of forfeitures	7,307					6,974		333
Income tax benefit of equity compensation	40					40
Stock option compensation expense, net of forfeitures	2,368					2,368
Restricted stock grant (in shares)				300
Restricted stock grant				3		(3)
Stock options exercised (in shares)				1,695
Stock options exercised	28,538			16		28,522
Ending Balance at Sep. 30, 2013	1,506,948			1,158		1,721,497		(215,707)
Ending Balance (in shares) at Sep. 30, 2013				115,831
Beginning Balance at Dec. 31, 2013	1,502,507			1,159		1,725,363		(224,015)
Beginning Balance (in shares) at Dec. 31, 2013				115,923
Net income	165,016							165,016
Retirement of common stock (in shares)				(92)
Retirement of common stock	(3,052)			(1)		(3,051)
Dividend on common stock		(179,190)							(179,190)
Restricted stock compensation, net of forfeitures (in shares)				(14)
Restricted stock compensation, net of forfeitures	8,975					8,898		77
Income tax benefit of equity compensation	222					222
Stock option compensation expense, net of forfeitures	1,463					1,463
Restricted stock grant (in shares)				267
Restricted stock grant	3			3
Stock options exercised (in shares)				392
Stock options exercised	6,349			4		6,345
Ending Balance at Sep. 30, 2014	$ 1,502,293			$ 1,165		$ 1,739,240		$ (238,112)
Ending Balance (in shares) at Sep. 30, 2014				116,476