Taxes - Provision for (Benefit from) Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current Provision for Income Taxes
Federal	$ 512	$ 1,477	$ 144
State	361	331	167
Total Current Provision for Income Taxes	873	1,808	311
Deferred Provision for Income Taxes
Federal	10,991	1,910	(10,198)
State	(112)	(10)	(459)
Total Deferred Provision for (Benefit from) Income Taxes	10,879	1,900	(10,657)
Total Provision for Income Taxes	$ 11,752	$ 3,708	$ (10,346)