Income Taxes - Reconciliation of Effective Tax Rate (Details)	0 Months Ended	3 Months Ended		6 Months Ended
	Feb. 14, 2008	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Tax Disclosure [Abstract]
Federal statutory tax rate	38.00%	35.00%	35.00%	35.00%	35.00%
State income taxes, net of federal benefit		3.30%	3.40%	2.90%	2.70%
Change in valuation allowance		(0.30%)	0.50%	(0.20%)	(4.20%)
Warrant liability fair value adjustment		0.00%	(6.50%)	0.00%	(1.70%)
Domestic production activities deduction		(2.40%)	(2.50%)	(2.40%)	(2.30%)
Other		0.30%	(0.70%)	0.30%	0.10%
Effective income tax rate		35.90%	29.20%	35.60%	29.60%