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Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 3,056	$ 1,790
Rental income	15,341	16,100
Total revenue	18,397	17,890
Compressors - sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,891	852
Flares - sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	46	80
Other (parts/rebuilds) - sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	774	518
Service and maintenance
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	345	340
Total revenue	$ 345	$ 340

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