Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Property and Equipment
Proved oil and gas properties	$ 833,202	$ 658,519
Unproved oil and gas properties	54,986	50,377
Furniture, fixtures, and other equipment	3,520	3,270
Less - Accumulated depreciation, depletion, and amortization	(261,763)	(216,769)
Net Furniture, Fixtures and other equipment	629,945	495,397
Accounts Payable and Accrued Liabilities
Trade accounts payable	26,040	20,884
Accrued operating expenses	3,062	3,490
Accrued compensation costs	3,860	5,334
Asset retirement obligation - current portion	469	2,109
Accrued non-income based taxes	8,237	3,898
Accrued corporate and legal fees	2,547	2,784
Other payables	3,893	5,938
Total accounts payable and accrued liabilities	48,108	44,437
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	4,542	7,806	$ 12,861
Long-term restricted cash	0	220	220
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 4,542	$ 8,026	$ 13,081	$ 497

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

Name:	us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.