Segment Information - Additional Information (Detail) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($) Employees Pilot	Jun. 30, 2015	Jun. 30, 2016 USD ($) Aircraft Segment Entity Location States	Jun. 30, 2015
Segment Reporting Information [Line Items]
Number of reportable segments | Segment				3
Number of aircraft operated				100
Fixed revenue streams | Entity				0
Hospitals Contracts [Member]
Segment Reporting Information [Line Items]
Segment revenue	29.00%		36.00%	30.00%	39.00%
Voluntary Employee Retirement Package [Member]
Segment Reporting Information [Line Items]
Qualifying age				64 years
Number of employees accepted VERP | Employees		15
Severance costs | $		$ 1.6
Remaining unpaid portion of severance costs | $	$ 0.4			$ 0.4
Voluntary Furlough Program to Oil and Gas Pilots [Member]
Segment Reporting Information [Line Items]
Severance costs | $		$ 0.4
Number of employees accepted furlough program | Pilot		26
Guaranteed period to recall under program		12 months
Oil and Gas [Member]
Segment Reporting Information [Line Items]
Number of aircraft available for use				145
Segment revenue	50.00%		57.00%	52.00%	58.00%
Oil and Gas [Member] | Minimum [Member] | Major Customer [Member]
Segment Reporting Information [Line Items]
Working period with major customers				30 years
Oil and Gas [Member] | Minimum [Member] | ENI Petroleum [Member]
Segment Reporting Information [Line Items]
Working period with major customers				15 years
Air Medical [Member]
Segment Reporting Information [Line Items]
Segment revenue	45.00%		41.00%	44.00%	38.00%
Number of aircraft assigned				105
Number of states in which company operates aircrafts | States				18
Locations in which company operates Aircrafts | Location				72
Air Medical [Member] | Middle East [Member]
Segment Reporting Information [Line Items]
Number of aircraft operated				8
Locations in which company operates Aircrafts | Location				3
Number of revenue generating aircrafts				4
Technical Services [Member]
Segment Reporting Information [Line Items]
Segment revenue	5.00%		2.00%	4.00%	4.00%