Income Taxes - Components of Provision for Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income (loss) before income taxes:
Domestic	$ 176,494	$ 119,974	$ 94,349
International	5	1,658	(1,510)
Income before Income Taxes	176,499	121,632	92,839
Current provision:
Federal	51,144us-gaap_CurrentFederalTaxExpenseBenefit	37,639us-gaap_CurrentFederalTaxExpenseBenefit	35,327us-gaap_CurrentFederalTaxExpenseBenefit
International	46us-gaap_CurrentForeignTaxExpenseBenefit	56us-gaap_CurrentForeignTaxExpenseBenefit	17us-gaap_CurrentForeignTaxExpenseBenefit
State and local	1,753	682	1,049
Total current provision for income taxes	52,943us-gaap_CurrentIncomeTaxExpenseBenefit	38,377us-gaap_CurrentIncomeTaxExpenseBenefit	36,393us-gaap_CurrentIncomeTaxExpenseBenefit
Deferred provision (benefit):
Federal	11,363	5,122	(2,399)
State and local	522	95	(27)
Total deferred provision (benefit) for income taxes	11,885us-gaap_DeferredIncomeTaxExpenseBenefit	5,217us-gaap_DeferredIncomeTaxExpenseBenefit	(2,426)us-gaap_DeferredIncomeTaxExpenseBenefit
Total provision for income taxes	$ 64,828us-gaap_IncomeTaxExpenseBenefit	$ 43,594us-gaap_IncomeTaxExpenseBenefit	$ 33,967us-gaap_IncomeTaxExpenseBenefit

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

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