Acquisitions and Dispositions (Details) - USD ($) $ in Thousands			12 Months Ended
	Jan. 24, 2018	Jul. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 22, 2017	Nov. 06, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments to Acquire Oil and Gas Property			$ 1,002	$ 9,426
Payments for (Proceeds from) Other Investing Activities			8,740	0
AWP Olmos Wheeler Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment		$ 700
Buyer's Assumption of ARO		$ 600
AWP working interest acquisition [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Buyer's Assumption of ARO						$ 200
Payments to Acquire Oil and Gas Property				$ 9,400
Bay De Chene [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase and sale contract					$ 16,300
Cash to be released for purchase and sale contract			$ 7,500
AWP Olmos Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment	$ 27,000
Buyer's Assumption of ARO	$ 6,300