Segment Information - Schedule of Net Revenue Attributable to Insurance, Medicare, Medicaid, and Self-Pay as Percentage of Net Air Medical Revenues (Detail) - Air Medical [Member]	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Insurance [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	70.00%	66.00%
Medicare [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	20.00%	19.00%
Medicaid [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	10.00%	15.00%
Self Pay [Member]
Segment Reporting Information [Line Items]
Percentage of net Air Medical revenues	0.00%	0.00%