Income Taxes - Summary of Reconciliation of Statutory Federal Tax and Effective Income Tax Rates (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disclosure Income Taxes Summary Of Reconciliation Of Statutory Federal Tax And Effective Income Tax Rates [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%
Reconciliation of Effective Income Tax Rates Continuing Operations
Federal income tax expense (1)	[1]	$ 34.0	$ 24.2	$ 26.0
State income taxes, net of federal benefit (2)	[2]	8.4	4.4	7.7
Other		0.8	(0.5)	0.1
Total Income Tax Expense		$ 43.2	$ 28.1	$ 33.8
Effective Income Tax Rate		26.71%	24.35%	27.34%

[1] 1) Federal income taxes were calculated at 21 percent for 2024, 2023, and 2022.

[2] (2) 2023 includes the impact of the one-time benefit associated with the reduction in the Pennsylvania state tax rate. See Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations for an additional information