Income Taxes - Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current [Abstract]
Federal	$ 18,448	$ 17,761	$ 14,537
State	2,166	2,068	1,237
Deferred [Abstract]
Federal	12,865	16,256	18,394
State	1,935	2,444	2,769
Income tax provision	$ 35,414	$ 38,529	$ 36,937