Acquisition (Preliminary Purchase Price Allocation) (Details) - Petrobas America Inc [Member] $ in Thousands	1 Months Ended
	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Cash consideration paid to PAI	$ 788,724
Fair value of net assets contributed	154,469
Contingent consideration	52,540
NCI in acquired assets	248,933
Total purchase consideration	1,244,666
Fair value of Property, Plant and Equipment	1,627,429
Other assets	5,628
Less: Asset retirement obligations	(388,391)
Total net assets	$ 1,244,666