Revenue Recognition - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Contract liability	$ 0								$ 0
Contract asset	0								0
Total revenues	$ 72,177,000	$ 71,467,000	$ 66,558,000	$ 61,421,000	$ 56,883,000	$ 47,381,000	$ 40,312,000	$ 37,640,000	271,623,000	$ 182,216,000	$ 120,852,000
Midstream Services
Disaggregation of Revenue [Line Items]
Total revenues									250,820,000	170,178,000	108,366,000
Product Sales
Disaggregation of Revenue [Line Items]
Total revenues									20,803,000	12,038,000	12,486,000
Crude oil and natural gas revenues | Midstream Services
Disaggregation of Revenue [Line Items]
Total revenues									134,562,000	85,828,000	16,660,000
Produced and flowback water revenues | Midstream Services
Disaggregation of Revenue [Line Items]
Total revenues									116,258,000	84,350,000	91,706,000
Natural gas and NGL revenues | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues									1,445,000	0	0
Freshwater revenues | Product Sales
Disaggregation of Revenue [Line Items]
Total revenues									$ 19,358,000	$ 12,038,000	$ 12,486,000