Employee Benefit Plans - Changes In Benefit Obligations Recognized In Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Defined Benefit Pension Plans | |||
| Pension Plans Postretirement And Other Employee Benefits [Line Items] | |||
| Net actuarial gain (loss) | $ 2.7 | $ (103.9) | $ 14.7 |
| Plan curtailment | 7.1 | ||
| Settlements | (0.3) | ||
| Net actuarial loss | 14.1 | 10.3 | 13.0 |
| Prior service cost | 0.4 | 0.5 | 1.1 |
| Net transition obligations | 0.1 | 0.4 | |
| Total | 17.2 | (93.3) | 36.3 |
| OPEB | |||
| Pension Plans Postretirement And Other Employee Benefits [Line Items] | |||
| Net actuarial gain (loss) | 0.2 | (0.8) | 1.6 |
| Plan amendments/curtailment | 4.5 | ||
| Net actuarial loss | 0.3 | 0.2 | 0.3 |
| Prior service cost | (0.8) | (0.9) | (1.1) |
| Total | $ (0.3) | $ (1.5) | $ 5.3 |