Income Taxes - Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ 16,664	$ 15,298	$ 17,347
State	1,866	2,057	1,774
Current income tax expense (benefit)	18,530	17,355	19,121
Deferred:
Federal	4,930	6,103	2,025
State	1,227	(1,371)	890
Deferred income tax expense (benefit)	$ 6,157	$ 4,732	$ 2,915