Revenue Recognition (Disaggregation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Gathering and transportation lease revenues	$ 14,135	$ 13,148	$ 46,361	$ 38,634
Total revenues	20,916	18,152	60,261	53,727
Natural gas sales
Disaggregation of Revenue [Line Items]
Revenues	177	166	543	865
Oil sales
Disaggregation of Revenue [Line Items]
Revenues	4,769	2,848	7,841	7,894
Natural gas liquid product
Disaggregation of Revenue [Line Items]
Revenues	115	408	411	1,403
Gathering and transportation
Disaggregation of Revenue [Line Items]
Revenues	1,720	1,582	5,105	4,931
Production
Disaggregation of Revenue [Line Items]
Total revenues	5,061	3,422	8,795	10,162
Production | Natural gas sales
Disaggregation of Revenue [Line Items]
Revenues	177	166	543	865
Production | Oil sales
Disaggregation of Revenue [Line Items]
Revenues	4,769	2,848	7,841	7,894
Production | Natural gas liquid product
Disaggregation of Revenue [Line Items]
Revenues	115	408	411	1,403
Midstream
Disaggregation of Revenue [Line Items]
Gathering and transportation lease revenues	14,135	13,148	46,361	38,634
Total revenues	15,855	14,730	51,466	43,565
Midstream | Gathering and transportation
Disaggregation of Revenue [Line Items]
Revenues	$ 1,720	$ 1,582	$ 5,105	$ 4,931