Revenue from Contracts with Customers (Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Contract liability	$ 2,724	$ 4,172
Mid-Stream [Member]
Disaggregation of Revenue [Line Items]
Current contract assets	3,226	6,084
Non-current contract assets	0	173
Contract assets	3,226	6,257
Contract with Customer, Current Asset, Reclassified to Receivable	(2,858)
Contract with Customer, Non-current Asset, Reclassified to Receivable	(173)
Change in contract assets	(3,031)
Current Contract Liabilities	2,098	2,583
Non-current contract liabilities	626	1,589
Contract liability	2,724	4,172
Contract with Customer, Current Liability, Revenue Recognized	(485)
Contract with Customer, Non-current Liability, Revenue Recognized	(963)
Change in contract assets (liabilities)	(1,448)
Contract asset (liabilities), net	502	$ 2,085
Change in contract liabilities	$ (1,583)