Consolidated Statement of Stockholders' Equity (USD $) In Thousands	Total	Regular Dividend	Common Stock	Additional Paid-in Capital	(Accumulated Deficit) Retained Earnings	(Accumulated Deficit) Retained Earnings Regular Dividend
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 grants (in shares)			245
Restricted stock grants	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
Beginning Balance at Dec. 31, 2014	1,481,500		1,168	1,748,303	(267,971)
Beginning Balance (in shares) at Dec. 31, 2014			116,764
Net income	57,277				57,277
Retirement of common stock (in shares)			(230)
Retirement of common stock	(9,261)		(2)	(9,259)
Dividend on common stock		(63,621)				(63,621)
Restricted stock compensation, net of forfeitures (in shares)			(3)
Restricted stock compensation, net of forfeitures	3,426			3,392	34
Income tax benefit of equity compensation	379			379
Stock option compensation expense, net of forfeitures	372			372
Restricted stock grants (in shares)			293
Restricted stock grants	3		3
Stock options exercised (in shares)			176
Stock options exercised	3,541		1	3,540
Ending Balance at Mar. 31, 2015	$ 1,473,616		$ 1,170	$ 1,746,727	$ (274,281)
Ending Balance (in shares) at Mar. 31, 2015			117,000