Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Income Tax Disclosure [Abstract] | ||
| Uncertain tax benefits accrued, beginning balance | $ 4.0 | $ 3.9 |
| Additions for tax positions related to current year | 0.0 | 0.3 |
| Additions for tax positions of prior years | 1.0 | 0.0 |
| Reductions for tax positions of prior years | 0.0 | 0.0 |
| Lapse of statute of limitations | (0.3) | (0.2) |
| Settlements | 0.0 | 0.0 |
| Uncertain tax benefits accrued, ending balance | $ 4.7 | $ 4.0 |