Acquisitions (Preliminary Purchase Price Allocation) (Details) - LLOG Exploration Offshore L.L.C. and LLOG Bluewater Holdings, L.L.C. - USD ($) $ in Thousands	1 Months Ended	7 Months Ended
	Jun. 30, 2019	Dec. 31, 2019	Mar. 31, 2020
Business Acquisition [Line Items]
Cash consideration paid	$ 1,236,200	$ 1,236,165
Contingent consideration		89,444
Total purchase consideration		$ 1,325,609
Fair value of Property, plant and equipment			$ 1,356,185
Other assets			6,697
Less: Asset retirement obligations			(37,273)
Total net assets			$ 1,325,609