Income Taxes - Reconciliation of Beginning and End of Period Amounts of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
|
| Income Tax Disclosure [Abstract] | |||
| Balance at beginning of period | $ 145.5 | $ 176.6 | $ 190.5 |
| Increase related to prior periods | 0.1 | 1.1 | 0.7 |
| Decrease related to prior periods | (7.9) | (23.3) | (0.3) |
| Increase related to current periods | 5.5 | 5.1 | 5.9 |
| Decrease related to settlements with taxing authorities | (0.3) | (13.4) | (7.5) |
| Decrease related to lapse in statutes of limitations | (3.2) | (0.6) | (12.7) |
| Balance at end of period | $ 139.7 | $ 145.5 | $ 176.6 |