Income Taxes - Changes in Amount of Uncertain Tax Positions (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Changes in unrecognized tax benefits: | |||
| Unrecognized tax benefits at beginning of year | $ 9.7 | $ 10.4 | $ 15.9 |
| Net increase (decrease): | |||
| Tax positions taken in prior periods | (0.1) | (0.3) | (5.4) |
| Tax positions taken in current period | 2.5 | 1.1 | 1.1 |
| Lapse due to applicable statute of limitations | (0.2) | (0.2) | |
| Settlements with taxing authorities | (2.3) | ||
| Change in currency exchange rates | 0.3 | (1.3) | (1.2) |
| Unrecognized tax benefits at end of year | $ 9.9 | $ 9.7 | $ 10.4 |