Discontinued Operations (Predecessor) (Total Operating and Investing Cash Flows of Discontinued Operations) (Details) - Predecessor - Weeks Island Field, Louisiana - Disposed of by Sale - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 08, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total operating cash flows of discontinued operations	$ 2,974	$ 21,138	$ 31,255
Total investing cash flows of discontinued operations	$ (601)	$ 6,891	$ (14,378)