Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Reconciliation, Other Reconciling Items [Abstract]
Income tax (benefit) at statutory rate	$ (3,802)	$ 1,129
State income taxes, net of federal tax benefit	(54)	211
Valuation allowance	(131,234)	14,595
Change in federal tax rate	33,640	0
Change in state tax rate	100,899	(16,475)
Bankruptcy reorganization	746	437
Uncertain tax positions	(4)	(35)
Other	(177)	117
Total income tax expense (benefit)	$ 14	$ (21)