Inventories - Schedule of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Unsold crude oil	$ 27,634	$ 17,318
Materials and supplies	48,489	62,706
Inventory, net, total	$ 76,123	$ 80,024	[1]

[1] Reclassified to conform with current presentation (see Note E)