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Segment Information (Details) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 USD ($) segment | Jun. 30, 2017 USD ($) | Jun. 30, 2018 USD ($) | Jun. 30, 2017 USD ($)
Segment Reporting Information [Line Items] |  |  |  |
Number of operating segments | segment | 1 |  |  |
Revenue | $ 18,204 | $ 16,218 | $ 32,922 | $ 35,120
Operating costs and corporate expenses | 17,978 | 15,804 | 32,346 | 34,363
Total other expense, net | 75 | 1 | (1) | 2
Income before provision for income taxes | 301 | 415 | 575 | 759
Corporate |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 0 | 0 | 0 | 0
Operating costs and corporate expenses | 7,758 | 7,700 | 15,166 | 16,074
Total other expense, net | 75 | 1 | (1) | 2
Income before provision for income taxes | (7,683) | (7,699) | (15,167) | (16,072)
Rental |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 11,427 | 11,420 | 22,898 | 23,342
Operating costs and corporate expenses | 5,195 | 4,255 | 9,899 | 8,923
Total other expense, net | 0 | 0 | 0 | 0
Income before provision for income taxes | 6,232 | 7,165 | 12,999 | 14,419
Sales |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 6,383 | 4,407 | 9,381 | 11,044
Operating costs and corporate expenses | 4,924 | 3,745 | 7,115 | 9,168
Total other expense, net | 0 | 0 | 0 | 0
Income before provision for income taxes | 1,459 | 662 | 2,266 | 1,876
Service and maintenance |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 394 | 391 | 643 | 734
Operating costs and corporate expenses | 101 | 104 | 166 | 198
Total other expense, net | 0 | 0 | 0 | 0
Income before provision for income taxes | $ 293 | $ 287 | $ 477 | $ 536

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- Definition Total costs of sales and operating expenses for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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