Segment Information - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2013 Contract Entity	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2013 Hospitals Contracts [Member]	Sep. 30, 2012 Hospitals Contracts [Member]	Sep. 30, 2013 Hospitals Contracts [Member]	Sep. 30, 2012 Hospitals Contracts [Member]	Sep. 30, 2013 Oil And Gas [Member]	Sep. 30, 2012 Oil And Gas [Member]	Sep. 30, 2013 Oil And Gas [Member] Aircraft	Sep. 30, 2012 Oil And Gas [Member]	Sep. 30, 2013 Oil And Gas [Member] Minimum [Member] Major Customer [Member]	Sep. 30, 2013 Oil And Gas [Member] Minimum [Member] ENI Petroleum [Member]	Sep. 30, 2013 Air Medical [Member]	Sep. 30, 2012 Air Medical [Member]	Sep. 30, 2013 Air Medical [Member] States Location Aircraft	Sep. 30, 2012 Air Medical [Member]	Sep. 30, 2013 Air Medical [Member] Middle East [Member] Aircraft Location	Sep. 30, 2013 Technical Services [Member]	Sep. 30, 2012 Technical Services [Member]	Sep. 30, 2013 Technical Services [Member]	Sep. 30, 2012 Technical Services [Member]
Segment Reporting Information [Line Items]
Working period with major customers												30 years	15 years
Number of Aircraft Operated										169						87		8
Segment revenue				38.00%	18.00%	38.00%	19.00%	63.00%	67.00%	63.00%	67.00%			36.00%	32.00%	36.00%	32.00%		1.00%	1.00%	1.00%	1.00%
Number of Aircraft Assigned																102
Number of states in which company operates aircrafts																18
Locations in which company operates Aircrafts																71		6
Number of Contracts	0
Fixed Revenue Streams	0
Allowance for contractual discounts	$ 67.4	$ 54.6	$ 57.1
Allowance for uncompensated care	$ 55.5	$ 48.0	$ 51.3