Segment Information - Schedule of Financial Information Concerning Reportable Operating Segments (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total operating revenues, net	$ 165,172		$ 169,243	$ 317,062	$ 329,607
Total direct expenses	153,514		155,083	310,390	311,309
Total selling, general and administrative expenses	17,591		14,485	42,458	29,944
Total net segment profit	(4,799)		(73)	(33,342)	(12,309)
Reorganization items, net	(26,503)	$ (1,600)		(28,103)
Interest expense	(3,927)		(8,340)	(12,093)	(16,537)
(Loss) earnings before income taxes	(34,896)		(8,777)	(73,245)	(30,250)
Reportable Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	165,172		169,243	317,062	329,607
Total direct expenses	152,475		155,002	307,990	311,264
Total selling, general and administrative expenses	8,965		7,994	17,165	16,452
Total segment direct and selling, general and administrative expenses	161,440		162,996	325,155	327,716
Total net segment profit	3,732		6,247	(8,093)	1,891
Reportable Operating Segments [Member] | Oil and Gas [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	90,023		97,068	174,969	192,702
Total direct expenses	89,061		94,442	179,031	190,985
Total selling, general and administrative expenses	4,672		4,400	9,432	9,321
Total net segment profit	(3,710)		(1,774)	(13,494)	(7,604)
Reportable Operating Segments [Member] | Air Medical [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	69,507		67,151	126,153	124,139
Total direct expenses	59,310		56,776	116,391	110,608
Total selling, general and administrative expenses	4,141		3,254	7,433	6,421
Total net segment profit	6,056		7,121	2,329	7,110
Reportable Operating Segments [Member] | Technical Services [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	5,642		5,024	15,940	12,766
Total direct expenses	4,104		3,784	12,568	9,671
Total selling, general and administrative expenses	152		340	300	710
Total net segment profit	1,386		900	3,072	2,385
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other, net	428		(193)	337	(2,112)
Reorganization items, net	(26,503)			(28,103)
Interest expense	(3,927)		(8,340)	(12,093)	(16,537)
Corporate [Member]
Segment Reporting Information [Line Items]
Unallocated selling, general and administrative costs	$ (8,626)		$ (6,491)	$ (25,293)	$ (13,492)