Fair Value of Financial Instruments - Schedule of Major Categories of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - U.S. Treasury Securities [Member] - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Assets:
Assets	$ 496.0	$ 24.7
Level 2 [Member]
Assets:
Assets	$ 496.0	$ 24.7