Revenue Recognition and Valuation Accounts - Additional Information (Detail) - USD ($) $ in Millions |
Mar. 31, 2017 |
Dec. 31, 2016 |
Mar. 31, 2016 |
|---|---|---|---|
| Valuation and Qualifying Accounts Disclosure [Line Items] | |||
| Allowance for doubtful accounts | $ 6.1 | $ 6.0 | |
| Value of uncompensated care services | 2.5 | $ 2.5 | |
| Estimated cost of providing charity services | 0.6 | $ 0.6 | |
| Valuation reserves related to obsolescence and slow moving inventory | 17.7 | 17.3 | |
| Air Medical [Member] | |||
| Valuation and Qualifying Accounts Disclosure [Line Items] | |||
| Allowance for contractual discounts against outstanding accounts receivable | 107.6 | 111.9 | |
| Allowance for uncompensated care against outstanding accounts receivable | $ 48.0 | $ 46.3 |