Treasury Stock and Share-Based Awards - Summary of Treasury Stock Activity (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($) shares
Treasury Stock, Number of Shares and Restriction Disclosures [Abstract]
Number of Treasury Shares | shares	6,000,000
Restricted stock withholdings | shares	270,000	[1]
Restricted stock forfeitures | shares	40,000.00	[2]
Number of Treasury Shares | shares	6,310,000
Beginning Balance, Cost | $	$ 98.3
Restricted stock withholdings | $	4.4	[1]
Restricted stock forfeitures | $	0.0	[2]
Ending Balance, Cost | $	$ 102.7

[1] Holdings withheld shares as a result of the election by certain employees to satisfy their tax liabilities upon vesting in restricted stock and performance stock units. Holdings determined the number of shares to be withheld based upon market values of the common stock of Holdings on the vesting dates, which ranged from $13.93 to $18.76 per share.

[2] Holdings repurchased forfeited restricted shares at a cost of $0.001 per share in accordance with its Long-Term Incentive Plan.