Income Taxes (Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Remeasurement of deferred taxes due to enacted tax rate change	$ (5,270)	$ 0	$ 0
Current:
Federal	0	0	0
State	100	1,200	1,200
Total current income tax expense (benefit)	100	1,200	1,200
Deferred:
Federal	(5,530)	1,862	2,478
State	1,471	280	309
Total deferred income tax expense (benefit)	(4,059)	2,142	2,787
Income tax expense (benefit)	$ (3,959)	$ 3,342	$ 3,987