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BUSINESS COMBINATIONS (2015 Acquisitions Narrative) (Details) - USD ($) $ in Thousands |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | ---
Apr. 11, 2015 | Dec. 31, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Business Acquisition [Line Items] |  |  |  |  |
Goodwill amount |  |  | $ 8,687 | $ 45,791 |
Thermo Fluids Inc. |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Purchase price | $ 79,300 |  |  |  |
Revenue from acquisition included in the company's result of operations |  |  |  | $ 38,000 | $ 33,800
Privately Owned Domestic Company |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |
Payments to acquire businesses |  | $ 14,700 |  |  |
Goodwill amount |  | $ 7,400 |  |  |

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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 + Details
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
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