Consolidated Statements of Redeemable Stock and Stockholders' Equity (Deficit) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Class B [Member]	Redeemable Series A Preferred Stock [Member]	Common Stock (Formerly Class A Common Stock) [Member]	Additional Paid-in Capital [Member]	Excess purchase price over predecessor basis [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Comprehensive Income Other[Member]	Stockholder Notes Receivables [Member]	Comprehensive Income (loss) [Member]
Balance at Dec. 31, 2008	$ (810,194)	$ 765,096	$ 78,355	$ 0	$ 2,356	$ (202,116)	$ (581,626)	$ (28,650)	$ (158)
Balance (in shares) at Dec. 31, 2008		24,018	7,835	1,736
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amortization of unrealized loss on interest rate swaps, net of tax	24,222	0	0	0	0	0	0	24,222	0	24,222
Repayment of stockholder notes receivable	129	0	0	0	0	0	0	0	129	0
Beneficial conversion related to Class B Common and Series A Preferred stockholders	0
Cancellation of stock	0	0	0	0	0	0	0	0	0	0
Cancellation of stock (in shares)				(118)
Contribution of capital related to debt extinguishment	0	0	14,754	0	0	0	0	0	0	0
Contribution of capital related to debt extinguishment (in shares)			1,476
Proceeds from shares issued to management and directors	0	0	497	0	0	0	0	0	0	0
Proceeds from shares issued to management and directors (in shares)			50
Proceeds from shares issued to stockholders	0	0	19,503	0	0	0	0	0	0	0
Proceeds from shares issued to stockholders (in shares)			1,950
Net income	43,055	0	0	0	0	0	43,055	0	0	43,055
Amortization of restricted stock expense	38	0	0	0	38	0	0	0	0	0
Pension liability adjustment, net of tax	(64)	0	0	0	0	0	0	(64)	0	(64)
Total Comprehensive Income										67,213
Balance at Dec. 31, 2009	(742,814)	765,096	113,109	0	2,394	(202,116)	(538,571)	(4,492)	(29)
Balance (in shares) at Dec. 31, 2009		24,018	11,311	1,617
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amortization of unrealized loss on interest rate swaps, net of tax	(4,145)	0	0	0	0	0	0	(4,145)	0	(4,145)
Repayment of stockholder notes receivable	29	0	0	0	0	0	0	0	29	0
Corporate reorganization	878,205	(765,096)	(113,109)	284	877,921	0	0	0	0	0
Corporate reorganization (in shares)		(24,018)	(11,311)	28,368,581
Beneficial conversion related to Class B Common and Series A Preferred stockholders	(140,690)	0	0	0	(140,690)	0	0	0	0	0
Accumulated accretion related to Class B Common and Series A Preferred stockholders	(303,305)	0	0	0	(303,305)	0	0	0	0	0
Issuance of Common stock (formerly Class A Common stock) resulting from the beneficial conversion and accumulated accretion	443,995	0	0	180	443,815	0	0	0	0	0
Issuance of Common stock (formerly Class A Common stock) resulting from the beneficial conversion and accumulated accretion (in shares)				18,002,337
Proceeds from public stock offering	247,631	0	0	207	247,424	0	0	0	0	0
Proceeds from public stock offering (in shares)				20,700,500
Net income	56,913	0	0	0	0	0	56,913	0	0	56,913
Share based compensation	6,363	0	0	5	6,358	0	0	0	0	0
Share based compensation (in shares)				451,561
Pension liability adjustment, net of tax	(1,115)	0	0	0	0	0	0	(1,115)	0	(1,115)
Total Comprehensive Income										51,653
Balance at Dec. 31, 2010	441,067	0	0	675	1,133,918	(202,116)	(481,658)	(9,752)	0
Balance (in shares) at Dec. 31, 2010				67,524,596
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amortization of unrealized loss on interest rate swaps, net of tax	(683)	0	0	0	0	0	0	(683)	0	(683)
Common stock issued under equity incentive plans, net of shares withheld for employee taxes	(62)	0	0	1	(63)	0	0	0	0	0
Common stock issued under equity incentive plans, net of shares withheld for employee taxes (in shares)				128,216
Excess tax benefits from equity awards	200	0	0	0	200	0	0	0	0	0
Beneficial conversion related to Class B Common and Series A Preferred stockholders	0
Net income	324,643	0	0	0	0	0	324,643	0	0	324,643
Share based compensation	8,646	0	0	0	8,646	0	0	0	0	0
Pension liability adjustment, net of tax	(4,922)	0	0	0	0	0	0	(4,922)	0	(4,922)
Balance at Dec. 31, 2011	$ 768,889	$ 0	$ 0	$ 676	$ 1,142,701	$ (202,116)	$ (157,015)	$ (15,357)	$ 0	$ 319,038
Balance (in shares) at Dec. 31, 2011				67,652,812