Variable Interest Entities (Details) - USD ($) $ in Thousands			7 Months Ended	9 Months Ended	12 Months Ended	15 Months Ended	24 Months Ended
	Nov. 22, 2016	Jul. 05, 2016	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2017	Jun. 30, 2017	Nov. 30, 2016
Variable Interest Entity [Line Items]
Capital investments				$ 117,699	$ 107,320	$ 117,699
Earnings in equity investments				6,800	2,301	6,800
Distributions received				(8,245)	(2,950)
Estimated earnout accrued				4,049	4,270	4,049
Equity in equity investments				120,303	110,941	120,303
Guarantees of capital investments				8,247	17,584	8,247
Maximum exposure to loss				128,550	$ 128,525	128,550
Carnero Processing Joint Venture
Variable Interest Entity [Line Items]
Ownership interest (as a percent)	50.00%							50.00%
Payments to acquire interest in joint venture	$ 55,500		$ 15,800
Assumption of capital commitments in joint venture	24,500
Debt incurred				0		0
Capital investments	$ 48,000			71,800		71,800
Maximum exposure to loss				80,400		80,400
Carnero Gathering LLC, Joint Venture
Variable Interest Entity [Line Items]
Ownership interest (as a percent)		50.00%
Payments to acquire interest in joint venture		$ 37,000		5,100		8,400	$ 8,400
Assumption of capital commitments in joint venture		$ 7,400
Debt incurred				0		0
Capital investments				45,900		45,900
Maximum exposure to loss				$ 48,100		$ 48,100