Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income before income tax expense	$ 26,458	$ 28,674
Income tax expense:
Federal income tax expense	7,101	7,076
State income tax expense	1,395	1,716
Total income tax expense	$ 8,496	$ 8,792
Effective income tax rate (percent)	32.10%	30.70%