Investment Securities - Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Proceeds from maturities and redemptions of available-for-sale securities	$ 0	$ 30,686
Gain Losses Maturities And Impairment	0	0
Sales
Net Investment Income [Line Items]
Gross Gains	0	0
Gross Losses	0	0
Gain Losses Maturities And Impairment	0	0
Maturities
Net Investment Income [Line Items]
Gross Gains	0	0
Gross Losses	0	0
Gain Losses Maturities And Impairment	$ 0	$ 0