Acquisition (Preliminary Purchase Price Allocation) (Details) $ in Thousands	1 Months Ended
	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Fair value of Property, Plant and Equipment	$ 1,617,052
Other assets	10,041
Less: Asset retirement obligations	(359,643)
Total net assets	1,267,450
Petrobas America Inc [Member]
Business Acquisition [Line Items]
Cash consideration paid to PAI	794,623
Fair value of net assets contributed	166,797
Fair value of contingent consideration	52,540
Noncontrolling interest in acquired assets	253,490
Total purchase consideration	$ 1,267,450