Income Taxes (Details) - Components of Income Tax Benefit - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Income before income tax expense	$ 34,451	$ 27,098	$ 96,564	$ 80,076
Income tax expense:
Federal income tax expense	9,036	6,714	24,956	19,719
State income tax expense	2,131	1,835	5,868	5,644
Total income tax expense	$ 11,167	$ 8,549	$ 30,824	$ 25,363
Effective income tax rate (percent)	32.40%	31.50%	31.90%	31.70%