Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Components of Deferred Tax Assets and Liabilities [Abstract]
Net operating loss carryforward	$ 112,409	$ 112,898
Stock-based compensation	1,368	1,962
Deferred rent	0	628
Financing obligation	2,163	1,174
Accrued expenses	38	250
Derivative instruments	287	0
Other assets	148	2,409
Capital loss carryforward	890	1,028
Less: Valuation allowance	(12,587)	(13,215)
Total long-term deferred tax assets	104,716	107,134
Oil and gas properties	(201,396)	(219,390)
Long-term derivative instruments	0	(26,700)
Prepaid expenses	(462)	(374)
Deferred compensation	(276)	(204)
Total long-term deferred tax assets (liabilities)	(202,134)	(246,668)
Net long-term deferred tax assets (liabilities)	$ (97,418)	$ (139,534)