Summary of Significant Accounting Policies and Related Matters - Impact of Adjustment on Income Tax Footnote Deferred Tax Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Federal and state NOL carry-forwards	$ 25,462	$ 44,649
Total gross deferred tax assets	63,924	89,459
Less valuation allowance	(62,688)	(88,171)
Net deferred tax assets	1,236	1,288
Net deferred tax liability	81,271	107,039
Previously Reported
Deferred tax assets:
Federal and state NOL carry-forwards		116,227
Total gross deferred tax assets		161,037
Less valuation allowance		(158,081)
Net deferred tax assets		2,956
Net deferred tax liability		105,371
Adjustment
Deferred tax assets:
Federal and state NOL carry-forwards		(71,578)
Total gross deferred tax assets	$ (1,600)	(71,578)
Less valuation allowance		69,910
Net deferred tax assets		(1,668)
Net deferred tax liability		$ 1,668