Schedule II: Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Allowances on Accounts Receivable [Member] | |||
| Valuation And Qualifying Accounts Disclosure [Line Items] | |||
| Balance at beginning of period | $ 11.5 | $ 8.0 | $ 9.0 |
| Charged to costs and expenses | 11.3 | 20.8 | 5.1 |
| Charged to other accounts | 1.0 | (0.1) | 2.0 |
| Deductions | (14.7) | (17.2) | (8.1) |
| Balance at end of period | 9.1 | 11.5 | 8.0 |
| Valuation Allowance for Deferred Tax Assets [Member] | |||
| Valuation And Qualifying Accounts Disclosure [Line Items] | |||
| Balance at beginning of period | 11.8 | 11.9 | 7.1 |
| Charged to costs and expenses | 3.5 | 2.5 | 4.7 |
| Charged to other accounts | (0.1) | (1.5) | (0.1) |
| Deductions | (1.1) | 0.2 | |
| Balance at end of period | $ 15.2 | $ 11.8 | $ 11.9 |