Revenue from Contracts with Customers (Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Contract liability	$ 3,462	$ 4,172
Mid-Stream [Member]
Disaggregation of Revenue [Line Items]
Current contract assets	4,735	6,084
Non-current contract assets	0	173
Contract assets	4,735	6,257
Contract with Customer, Current Asset, Reclassified to Receivable	(1,349)
Contract with Customer, Non-current Asset, Reclassified to Receivable	(173)
Change in contract assets	(1,522)
Current Contract Liabilities	2,332	2,583
Non-current contract liabilities	1,130	1,589
Contract liability	3,462	4,172
Contract with Customer, Current Liability, Revenue Recognized	(251)
Contract with Customer, Non-current Liability, Revenue Recognized	(459)
Change in contract assets (liabilities)	(710)
Contract asset (liabilities), net	1,273	$ 2,085
Change in contract liabilities	$ (812)