Consolidated Statement of Stockholders' Equity (USD $) In Thousands	Total	Regular Dividend	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Deficit Regular 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	181,092				181,092
Issuance of common stock	9			9
Retirement of common stock (in shares)			(143)
Retirement of common stock	(5,430)		(1)	(5,429)
Dividend on common stock		(53,844)				(53,844)
Restricted stock compensation, net of forfeitures (in shares)			(7)
Restricted stock compensation, net of forfeitures	2,202			2,202
Income tax benefit of equity compensation	23			23
Stock option compensation expense, net of forfeitures	1,003			1,003
Restricted stock grant (in shares)			298
Restricted stock grant			3	(3)
Stock options exercised (in shares)			849
Stock options exercised	15,227		8	15,219
Ending Balance at Mar. 31, 2013	1,661,902		1,011	1,159,512	501,379
Ending Balance (in shares) at Mar. 31, 2013			101,102
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	51,738				51,738
Retirement of common stock (in shares)			(84)
Retirement of common stock	(2,768)		(1)	(2,767)
Dividend on common stock		(59,697)				(59,697)
Restricted stock compensation, net of forfeitures (in shares)			(3)
Restricted stock compensation, net of forfeitures	2,681			2,661	20
Income tax benefit of equity compensation	103			103
Stock option compensation expense, net of forfeitures	612			612
Restricted stock grant (in shares)			245
Restricted stock grant	2		2
Stock options exercised (in shares)			258
Stock options exercised	3,838		3	3,835
Ending Balance at Mar. 31, 2014	$ 1,499,016		$ 1,163	$ 1,729,807	$ (231,954)
Ending Balance (in shares) at Mar. 31, 2014			116,339