v3.8.0.1
Segment Information - Schedule of Financial Information Concerning Reportable Operating Segments (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Segment Reporting Information [Line Items]        
Total operating revenues, net $ 150,167 $ 158,093 $ 431,209 $ 489,245
Total segment direct expenses 136,786 144,938 400,250 449,909
Total segment selling, general and administrative expenses 11,401 13,381 38,691 36,832
Total net segment profit 2,422 (509) (9,291) 6,084
Interest expense (8,027) (7,719) (24,305) (22,792)
Loss before income taxes (4,899) (7,766) (31,122) (15,137)
Reportable Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Total operating revenues, net 150,167 158,093 431,209 489,245
Total segment direct expenses 136,348 145,136 401,806 450,183
Total segment selling, general and administrative expenses 4,622 5,027 14,813 13,894
Total segment expenses 140,970 150,163 416,619 464,077
Total net segment profit 9,197 7,930 14,590 25,168
Reportable Operating Segments [Member] | Oil and Gas [Member]        
Segment Reporting Information [Line Items]        
Total operating revenues, net 75,700 77,551 222,098 249,173
Total segment direct expenses 81,467 82,832 236,878 262,148
Total segment selling, general and administrative expenses 1,148 1,705 4,501 4,838
Total net segment profit (6,915) (6,986) (19,281) (17,813)
Reportable Operating Segments [Member] | Air Medical [Member]        
Segment Reporting Information [Line Items]        
Total operating revenues, net 70,280 74,482 192,840 220,089
Total segment direct expenses 51,120 56,562 152,363 172,603
Total segment selling, general and administrative expenses 3,136 3,056 9,280 8,293
Total net segment profit 16,024 14,864 31,197 39,193
Reportable Operating Segments [Member] | Technical Services [Member]        
Segment Reporting Information [Line Items]        
Total operating revenues, net 4,187 6,060 16,271 19,983
Total segment direct expenses 3,761 5,742 12,565 15,432
Total segment selling, general and administrative expenses 338 266 1,032 763
Total net segment profit 88 52 2,674 3,788
Segment Reconciling Items [Member]        
Segment Reporting Information [Line Items]        
Other, net 710 377 2,471 5,425
Interest expense (8,027) (7,719) (24,305) (22,792)
Corporate [Member]        
Segment Reporting Information [Line Items]        
Unallocated selling, general and administrative costs $ (6,779) $ (8,354) $ (23,878) $ (22,938)