Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforward	$ 20,882	$ 20,442
Stock based compensation	1,891	2,593
Intangibles	351	682
Organizational expenses and other	2,900	3,864
Total deferred tax assets	26,024	27,581
Deferred tax liabilities:
Oil and gas properties and other property and equipment, principally due to intangible drilling costs	(38,558)	(66,772)
Loss on derivative instruments	4,429	1,371
Other		(200)
Net deferred tax liabilities	$ (8,105)	$ (38,020)