Segment Information - Schedule of Financial Information Concerning Reportable Operating Segments (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
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| Segment Reporting Information [Line Items] | |||||||||||
| Total operating revenues, net | $ 158,093 | $ 214,733 | $ 489,245 | $ 617,477 | |||||||
| Total direct expenses | 144,938 | 182,064 | 449,909 | 520,099 | |||||||
| Total segment selling, general and administrative expenses | 13,381 | 11,575 | 36,832 | 34,859 | |||||||
| Total | (509) | 21,184 | 6,084 | 62,508 | |||||||
| Interest expense | (7,719) | (7,366) | (22,792) | (21,691) | |||||||
| (Loss) earnings before income taxes | (7,766) | 14,290 | (15,137) | 42,318 | |||||||
| Reportable Operating Segments [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Total operating revenues, net | 158,093 | 214,733 | 489,245 | 617,477 | |||||||
| Total direct expenses | [1] | 145,136 | 182,139 | 450,183 | 520,348 | ||||||
| Total segment selling, general and administrative expenses | 5,027 | 3,929 | 13,894 | 11,841 | |||||||
| Total segment expenses | 150,163 | 186,068 | 464,077 | 532,189 | |||||||
| Total | 7,930 | 28,665 | 25,168 | 85,288 | |||||||
| Reportable Operating Segments [Member] | Air Medical [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Total operating revenues, net | 74,482 | 85,516 | 220,089 | 239,543 | |||||||
| Total direct expenses | [1] | 56,562 | 65,474 | 172,603 | 189,089 | ||||||
| Total segment selling, general and administrative expenses | 3,056 | 2,302 | 8,293 | 7,458 | |||||||
| Total | 14,864 | 17,740 | 39,193 | 42,996 | |||||||
| Reportable Operating Segments [Member] | Oil and Gas [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Total operating revenues, net | 77,551 | 121,190 | 249,173 | 354,425 | |||||||
| Total direct expenses | [1],[2] | 82,832 | 109,500 | 262,148 | 310,093 | ||||||
| Total segment selling, general and administrative expenses | 1,705 | 1,397 | 4,838 | 3,831 | |||||||
| Total | (6,986) | 10,293 | (17,813) | 40,501 | |||||||
| Reportable Operating Segments [Member] | Technical Services [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Total operating revenues, net | 6,060 | 8,027 | 19,983 | 23,509 | |||||||
| Total direct expenses | [1] | 5,742 | 7,165 | 15,432 | 21,166 | ||||||
| Total segment selling, general and administrative expenses | 266 | 230 | 763 | 552 | |||||||
| Total | 52 | 632 | 3,788 | 1,791 | |||||||
| Segment Reconciling Items [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Other, net | [3] | 377 | 637 | 5,425 | 1,739 | ||||||
| Interest expense | (7,719) | (7,366) | (22,792) | (21,691) | |||||||
| Unallocated Selling, General and Administrative Expenses [Member] | |||||||||||
| Segment Reporting Information [Line Items] | |||||||||||
| Unallocated selling, general and administrative costs | [1] | $ (8,354) | $ (7,646) | $ (22,938) | $ (23,018) | ||||||
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