v3.7.0.1

Segment Information - Depreciation and Amortization Expense Included in Direct Expenses and Unallocated Selling, General, and Administrative Costs (Detail) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2017 | Mar. 31, 2016
Reportable Operating Segments [Member] |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |
Depreciation and Amortization Expenses | $ 15,485 | $ 14,302
Reportable Operating Segments [Member] | Oil and Gas [Member] |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |
Depreciation and Amortization Expenses | 9,862 | 9,918
Reportable Operating Segments [Member] | Air Medical [Member] |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |
Depreciation and Amortization Expenses | 5,477 | 4,256
Reportable Operating Segments [Member] | Technical Services [Member] |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |
Depreciation and Amortization Expenses | 146 | 128
Corporate [Member] |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |
Depreciation and Amortization Expenses | $ 1,360 | $ 2,671

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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=66902209&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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