CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive (Loss) Gain [Member]
Beginning Balance at Dec. 31, 2011	$ 872,467	$ 824	$ 955,735	$ (84,092)
Beginning Balance, shares at Dec. 31, 2011		82,418,808
Equity-based compensation	1,191	3	1,188
Equity-based compensation, shares		318,200
Unrealized gain (loss) on derivatives, net of tax	(1,254)				(1,254)
Dividend declared to stockholders	(500,000)		(500,000)
Net income (loss)	77,444			77,444
Ending Balance at Dec. 31, 2012	449,848	827	456,923	(6,648)	(1,254)
Ending Balance, shares at Dec. 31, 2012		82,737,008
Equity-based compensation	320	1	319
Equity-based compensation, shares		33,228
Unrealized gain (loss) on derivatives, net of tax	294				294
Net income (loss)	(40,360)			(40,360)
Ending Balance at Mar. 31, 2013	$ 410,102	$ 828	$ 457,242	$ (47,008)	$ (960)
Ending Balance, shares at Mar. 31, 2013		82,770,236