Fair Value Measurement (Details) - Commodity contract derivatives - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	$ 23,531	$ (3,116)
Level 1
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	5,377	(84)
Level 2
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	18,154	(3,032)
Level 3
Assets (liabilities) measured at fair value
Assets (liabilities), fair value	$ 0	$ 0