Segment Information - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended			3 Months Ended		9 Months Ended		0 Months Ended	3 Months Ended		9 Months Ended				0 Months Ended	3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2014 Contract Entity	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2014 Hospitals Contracts [Member]	Sep. 30, 2013 Hospitals Contracts [Member]	Sep. 30, 2014 Hospitals Contracts [Member]	Sep. 30, 2013 Hospitals Contracts [Member]	Sep. 30, 2014 Oil and Gas [Member] Aircraft	Sep. 30, 2014 Oil and Gas [Member]	Sep. 30, 2013 Oil and Gas [Member]	Sep. 30, 2014 Oil and Gas [Member]	Sep. 30, 2013 Oil and Gas [Member]	Sep. 30, 2014 Oil and Gas [Member] Minimum [Member] Major Customer [Member]	Sep. 30, 2014 Oil and Gas [Member] Minimum [Member] ENI Petroleum [Member]	Sep. 30, 2014 Air Medical [Member] Aircraft	Sep. 30, 2014 Air Medical [Member]	Sep. 30, 2013 Air Medical [Member]	Sep. 30, 2014 Air Medical [Member] Aircraft States Location	Sep. 30, 2013 Air Medical [Member]	Sep. 30, 2014 Air Medical [Member] Middle East [Member] Aircraft	Sep. 30, 2014 Air Medical [Member] Middle East [Member] Location	Sep. 30, 2014 Technical Services [Member]	Sep. 30, 2013 Technical Services [Member]	Sep. 30, 2014 Technical Services [Member]	Sep. 30, 2013 Technical Services [Member]
Segment Reporting Information [Line Items]
Working period with major customers													30 years	15 years
Number of aircraft operated								173							90					9
Segment revenue				36.00%	38.00%	39.00%	38.00%		62.00%	63.00%	62.00%	63.00%				37.00%	36.00%	36.00%	36.00%			2.00%	1.00%	2.00%	1.00%
Number of aircraft assigned																		101
Number of states in which company operates aircrafts																		18
Locations in which company operates Aircrafts																		71			5
Number of contracts	0
Fixed revenue streams	0
Allowance for contractual discounts	$ 107.1	$ 74.7	$ 67.4
Allowance for uncompensated care	$ 36.6	$ 46.4	$ 55.5