Federal Income Taxes - Schedule of Components of Future Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 85,995	$ 80,491
Mineral properties	11,608	13,970
Capital loss carryforwards	618	618
Restoration reserves	1,623	1,478
Capitalized transaction costs	1,140	1,145
Other	5,562	946
Deferred tax assets	106,546	98,648
Valuation allowance	(101,523)	(96,203)
Net deferred tax assets	5,023	2,445
Prepaids and other	70	68
Deferred tax liabilities current	70	68
Derivatives	(956)	(956)
Property, plant and equipment	(4,137)	(1,557)
Deferred tax liabilities	(5,093)	(2,513)
Net deferred tax asset (liability)