Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 50.0	$ 42.7	$ 43.0
Unrecognized compensation cost	39.9
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	48.7	41.0	41.4
Unrecognized compensation cost	$ 39.5
Weighted-average period over which unrecognized compensation cost will be recognized	1 year 9 months 18 days
Incentive Compensation Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 0.8	1.1	1.0
Unrecognized compensation cost	$ 0.4
Weighted-average period over which unrecognized compensation cost will be recognized	1 year 3 months 18 days
Directors' Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 0.5	$ 0.6	$ 0.6
Unrecognized compensation cost	$ 0.0