Income Taxes - Provision (Benefit) for Income Taxes from Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal									$ 14,020	$ 12,637	$ 8,954
State									379	342	1,003
Current income tax expense (benefit)									14,399	12,979	9,957
Deferred:
Federal									(3,764)	(254)	3,174
State									300	808	(904)
Deferred income tax expense (benefit)									(3,464)	554	2,270
Total	$ (2,357)	$ 7,491	$ 2,947	$ 2,854	$ 3,775	$ 2,316	$ 3,570	$ 3,872	$ 10,935	$ 13,533	$ 12,227