v3.7.0.1
Segment Information - Schedule of Financial Information Concerning Reportable Operating Segments (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Segment Reporting Information [Line Items]    
Total operating revenues $ 134,618 $ 164,016
Total segment direct expenses 136,513 152,554
Total segment selling, general and administrative expenses 13,044 11,673
Total net segment profit (15,942) (570)
Interest expense (8,195) (7,533)
Loss before income taxes (23,073) (7,488)
Reportable Operating Segments [Member]    
Segment Reporting Information [Line Items]    
Total operating revenues 134,618 164,016
Total segment direct expenses 137,516 152,554
Total segment selling, general and administrative expenses 4,939 4,347
Total direct and selling, general and administrative expenses 142,455 156,901
Total net segment profit (7,837) 7,115
Reportable Operating Segments [Member] | Air Medical [Member]    
Segment Reporting Information [Line Items]    
Total operating revenues 55,338 70,060
Total segment direct expenses 50,842 57,044
Total segment selling, general and administrative expenses 2,881 2,595
Total net segment profit 1,615 10,421
Reportable Operating Segments [Member] | Oil and Gas [Member]    
Segment Reporting Information [Line Items]    
Total operating revenues 71,731 88,437
Total segment direct expenses [1] 81,728 91,916
Total segment selling, general and administrative expenses 1,720 1,528
Total net segment profit (11,717) (5,007)
Reportable Operating Segments [Member] | Technical Services [Member]    
Segment Reporting Information [Line Items]    
Total operating revenues 7,549 5,519
Total segment direct expenses 4,946 3,594
Total segment selling, general and administrative expenses 338 224
Total net segment profit 2,265 1,701
Segment Reconciling Items [Member]    
Segment Reporting Information [Line Items]    
Other, net [2] 1,064 256
Interest expense (8,195) (7,533)
Corporate [Member]    
Segment Reporting Information [Line Items]    
Unallocated selling, general and administrative costs [3] $ (8,105) $ (7,326)
[1] Includes Equity in loss of unconsolidated affiliate.
[2] Consists of gains on disposition of property and equipment and other income - net.
[3] Included in segment direct expenses and unallocated selling, general, and administrative costs are the depreciation and amortization expense amounts below: Depreciation and Amortization Expense Quarter Ended March 31, 2017 2016 (Thousands of dollars) Segment Direct Expense: Oil and Gas $ 9,862 $ 9,918 Air Medical 5,477 4,256 Technical Services 146 128 Total $ 15,485 $ 14,302 Unallocated SG&A $ 1,360 $ 2,671