SEGMENT INFORMATION - Depreciation and Amortization Expense Included in Direct Expenses and Unallocated Selling, General, and Administrative Costs (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Reportable operating segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	$ 9,663	$ 8,114	$ 18,837	$ 16,238
Reportable operating segments [Member] | Oil And Gas [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	6,814	5,738	13,303	11,528
Reportable operating segments [Member] | Air Medical [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	2,837	2,354	5,503	4,665
Reportable operating segments [Member] | Technical Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	12	22	31	45
Unallocated S,G & A [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and Amortization Expenses	$ 963	$ 266	$ 2,026	$ 545