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Rental Equipment, Property and Equipment (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) compressor $ / shares	Dec. 31, 2018 USD ($) compressor	Dec. 31, 2017 USD ($)
Property, Plant and Equipment [Line Items]
Depreciation									$ 23,143	$ 21,954	$ 21,191
Net income (loss)	$ (1,710)	$ (12,579)	$ 327	$ 98	$ (749)	$ (118)	$ 211	$ 190	(13,864)	(466)	19,794
Retirement of rental equipment									1,512	0	0
Property, Plant, and Equipment, Excluding Rental Equipment
Property, Plant and Equipment [Line Items]
Depreciation									$ 1,700	$ 1,100	1,200
Rental Compressor Unit
Property, Plant and Equipment [Line Items]
Number of units retired | compressor									327	13
Rental Compressor Unit | Loss On Retirement of Rental Equipment
Property, Plant and Equipment [Line Items]
Retirement of rental equipment									$ 1,500
Revisions | Revision Of Prior Period Financial Statements
Property, Plant and Equipment [Line Items]
Depreciation									1,470
Net income (loss)		$ (347)	$ (246)	$ (259)	$ (467)	$ (354)	$ (36)	$ (35)	$ 1,130	$ (892)	(57)
Earnings per share, basic and diluted (in dollars per share) | $ / shares									$ 0.09
Rental Equipment
Property, Plant and Equipment [Line Items]
Depreciation									$ 21,400	$ 20,900	$ 20,000
Rental Equipment | Compressor Units, 1,380 Horsepower
Property, Plant and Equipment [Line Items]
Useful Lives									25 years
Minimum
Property, Plant and Equipment [Line Items]
Useful Lives									3 years
Minimum | Rental Equipment
Property, Plant and Equipment [Line Items]
Useful Lives									15 years
Minimum | Rental Equipment | Compressor Units, 400-600 Horsepower
Property, Plant and Equipment [Line Items]
Useful Lives									15 years
Minimum | Rental Equipment | Compressor Unit, Peer Horsepower
Property, Plant and Equipment [Line Items]
Useful Lives									20 years
Maximum
Property, Plant and Equipment [Line Items]
Useful Lives									39 years
Maximum | Rental Equipment
Property, Plant and Equipment [Line Items]
Useful Lives									25 years
Maximum | Rental Equipment | Compressor Units, 400-600 Horsepower
Property, Plant and Equipment [Line Items]
Useful Lives									20 years
Maximum | Rental Equipment | Compressor Unit, Peer Horsepower
Property, Plant and Equipment [Line Items]
Useful Lives									30 years

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