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Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue from External Customer [Line Items]
Revenue	$ 18,245	$ 15,765	$ 54,391	$ 51,060
Revenue related to unsatisfied performance obligations	0		0
Uncertain tax position	$ 0		0
Sales
Revenue from External Customer [Line Items]
Revenue recognized			1,100		$ 533
Rental income
Revenue from External Customer [Line Items]
Revenue recognized			2		$ 73
Bill and Hold Arrangement
Revenue from External Customer [Line Items]
Revenue			$ 0	$ 852
Minimum
Revenue from External Customer [Line Items]
Amortization period of capitalized contract costs	1 year		1 year
Rental Contracts, Excluding Large Horsepower Compressors | Minimum
Revenue from External Customer [Line Items]
Rental contract term	6 months		6 months
Rental Contracts, Excluding Large Horsepower Compressors | Maximum
Revenue from External Customer [Line Items]
Rental contract term	24 months		24 months
Rental Contracts, Large Horsepower Compressors | Maximum
Revenue from External Customer [Line Items]
Rental contract term	60 months		60 months

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