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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reportable Operating Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	$ 15,191	$ 15,313	$ 30,676	$ 29,614
Reportable Operating Segments [Member] | Oil and Gas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	9,824	10,024	19,686	19,942
Reportable Operating Segments [Member] | Air Medical [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	5,219	5,132	10,696	9,387
Reportable Operating Segments [Member] | Technical Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	148	157	294	285
Corporate [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	$ 622	$ 2,476	$ 3,335	$ 5,147

X

- 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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X

- 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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