Segment Information - Schedule of Profit or Loss and Assets of Each of Company's Reportable Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Total operating revenues, net	$ 197,071	$ 178,968
Total segment selling, general and administrative expenses	9,328	8,266
Total net segment profit (loss)	27,976	21,987
Interest expense	(7,364)	(7,409)
Loss on debt extinguishment	(29,216)
(Loss) earnings before income taxes	(8,513)	14,730
Reportable operating segments [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	197,071	178,968
Total segment direct expenses	158,694	148,690
Total segment selling, general and administrative expenses	3,189	2,753
Total direct and selling, general and administrative expenses	161,883	151,443
Total net segment profit (loss)	35,188	27,525
Reportable operating segments [Member] | Oil And Gas [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	125,975	112,831
Total segment direct expenses	97,374	92,873
Total segment selling, general and administrative expenses	1,034	913
Total net segment profit (loss)	27,567	19,045
Reportable operating segments [Member] | Air Medical [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	67,952	63,387
Total segment direct expenses	59,379	53,996
Total segment selling, general and administrative expenses	2,153	1,840
Total net segment profit (loss)	6,420	7,551
Reportable operating segments [Member] | Technical Services [Member]
Segment Reporting Information [Line Items]
Total operating revenues, net	3,144	2,750
Total segment direct expenses	1,941	1,821
Total segment selling, general and administrative expenses	2
Total net segment profit (loss)	1,201	929
Other, net [Member]
Segment Reporting Information [Line Items]
Total net segment profit (loss)	(982)	127
Unallocated Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Total net segment profit (loss)	$ (6,139)	$ (5,513)