Fair Value of Assets and Liabilities - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net change in unrealized gains (losses) on investments, net of tax	$ 0.1
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net change in unrealized gains (losses) on investments, net of tax		$ 0.5	$ 0.1