Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) - Failed Auction Security [Member] $ in Thousands	Sep. 30, 2024 USD ($)
Debt Securities, Available-for-Sale [Line Items]
Due in twenty to forty years, Cost	$ 3,000
Due in twenty to forty years, Estimated Fair Value	$ 2,640