v3.7.0.1
Segment Information - Schedule of Provisions for Contractual Discounts and Estimated Uncompensated Care as a Percentage of Gross Segment Billings (Detail) - Air Medical [Member]
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Provisions For Contractual Discounts And Estimated Uncompensated Care [Line Items]        
Provision for contractual discounts 63.00% 65.00% 66.00% 69.00%
Provision for uncompensated care 10.00% 7.00% 7.00% 4.00%