Supplemental Cash Flow Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Cash paid during the period for:
Interest payments	$ 4,217	$ 967
Non-cash transactions:
Accounts receivable	489
Prepaid expense	(17,076)
Commodity derivative asset - current	(2,178)
Inventory	900
Proved oil and gas properties	(900)
Unproved oil and gas properties	(139,613)
Other fixed assets	(3,364)
Equity method investments	14,655	5,674
Other non-current assets	(989)
Accounts payable and accrued liabilities	26,292	67
Commodity derivative liability - non-current	2,645
Firm transportation contract obligations	18,724
Warrant liability	(1,792)
Notes payable	83,006
Asset retirement obligations	$ 7,879	$ 2,402

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