v3.8.0.1

Segment Information - Depreciation and Amortization Expense Included in Direct Expenses and Unallocated Selling, General, and Administrative Costs (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016
Reportable Operating Segments [Member] |  |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |  |
Depreciation and Amortization Expenses | $ 14,646 | $ 16,024 | $ 45,322 | $ 45,638
Reportable Operating Segments [Member] | Oil and Gas [Member] |  |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |  |
Depreciation and Amortization Expenses | 9,615 | 10,616 | 29,301 | 30,558
Reportable Operating Segments [Member] | Air Medical [Member] |  |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |  |
Depreciation and Amortization Expenses | 4,885 | 5,267 | 15,581 | 14,654
Reportable Operating Segments [Member] | Technical Services [Member] |  |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |  |
Depreciation and Amortization Expenses | 146 | 141 | 440 | 426
Corporate [Member] |  |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |  |
Depreciation and Amortization Expenses | $ 1,936 | $ 2,269 | $ 5,271 | $ 7,416

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- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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