Revenue from Contracts with Customers (Contract with Customer, Asset and Liability) (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contract liability		$ 7,787	$ 9,881
Mid-Stream [Member]
Disaggregation of Revenue [Line Items]
Contract assets	[1]	12,999	13,164
Amounts invoiced in excess of revenue recognized		(165)
Contract with Customer, Asset, Net, Current		5,000	300
Contract with Customer, Asset, Net, Noncurrent		8,000	12,900
Contract liability	[2]	7,787	9,882
New contract		60
Contract with Customer, Liability, Revenue Recognized		(2,155)
Contract with Customer, Liability, Current		2,900	2,900
Contract with Customer, Liability, Noncurrent		$ 4,900	$ 7,000

[1] At December 31, 2018, total contract assets are included in prepaid expenses and other and other assets of $0.3 million and $12.9 million, respectively, in our Consolidated Balance Sheet. At September 30, 2019, total contract assets included prepaid expenses and other and other assets of $5.0 million and $8.0 million, respectively, in our Condensed Consolidated Balance Sheet.

[2] At December 31, 2018, total contract liabilities are included in current portion of other long-term liabilities and other long-term liabilities of $2.9 million and $7.0 million, respectively, in our Consolidated Balance Sheet. At September 30, 2019, total contract liabilities included current portion of other long-term liabilities and other long-term liabilities of $2.9 million and $4.9 million, respectively, in our Condensed Consolidated Balance Sheet.