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Basis of Presentation and Summary of Significant Accounting Policies (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer, excluding assessed tax | $ 6,323 | $ 6,777 | $ 10,927 | $ 10,024
Add: non-ASC 606 rental revenue | 13,572 | 11,427 | 26,959 | 22,898
Revenue | 19,895 | 18,204 | 37,886 | 32,922
Compressors - sales |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer, excluding assessed tax | 4,788 | 4,735 | 7,496 | 6,564
Flares - sales |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer, excluding assessed tax | 106 | 969 | 541 | 1,491
Other (Parts/Rebuilds) - sales |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer, excluding assessed tax | 920 | 679 | 1,902 | 1,326
Service and maintenance |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue from contract with customer, excluding assessed tax | 509 | 394 | 988 | 643
Revenue | $ 509 | $ 394 | $ 988 | $ 643

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