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Summary of Significant Accounting Policies (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	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]
Revenue from contracts with customers									$ 36,806	$ 40,065	$ 37,637
Add: non-ASC 606 rental revenue									28,672	27,628	34,017
Total revenue	$ 16,160	$ 16,396	$ 18,204	$ 14,718	$ 16,660	$ 15,913	$ 16,218	$ 18,902	65,478	67,693	71,654
Compressor - sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									10,994	13,382	10,038
Flares - sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,535	2,755	1,183
Other (Parts/Rebuilds) - sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									2,740	4,071	2,400
Service and maintenance
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers									$ 20,537	$ 19,857	$ 24,016

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