Retirement Plans - Summary of Plan's Assets Carried at Fair Value (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Total fair value	$ 228.9	$ 212.5	$ 282.3
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	120.3	112.9
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value	$ 108.6	$ 99.6	$ 124.2