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Major Customers (Details) - USD ($) | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Product and Service [Domain] |  |
Revenue, Major Customer [Line Items] |  |
Revenues | $ 72,266,000 | $ 63,046,000
Product and Service [Domain] | Navistar [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenues | 14,292,000 | 10,951,000
Product and Service [Domain] | Volvo [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenues | 14,622,000 | 10,197,000
Product and Service [Domain] | Paccar [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenues | 11,985,000 | 9,966,000
Product and Service [Domain] | Other Customers [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenues | 31,367,000 | 31,932,000
Product [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 71,451,000 | 59,712,000
Product [Member] | Navistar [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 14,253,000 | 10,951,000
Product [Member] | Volvo [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 14,515,000 | 10,197,000
Product [Member] | Paccar [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 11,812,000 | 6,763,000
Product [Member] | Other Customers [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 30,871,000 | 31,801,000
Service [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 815,000 | 3,334,000
Service [Member] | Navistar [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 39,000 | 0
Service [Member] | Volvo [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 107,000 | 0
Service [Member] | Paccar [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | 173,000 | 3,203,000
Service [Member] | Other Customers [Member] |  |
Revenue, Major Customer [Line Items] |  |
Revenue from Contract with Customer, Including Assessed Tax | $ 496,000 | $ 131,000

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- Definition Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045 + Details
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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8933-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 + Details
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