Securities - Schedule of Other Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Other Securities [Line Items]
Other securities	$ 473,255	$ 349,758
FRB and FHLB stock [Member]
Schedule of Other Securities [Line Items]
Other securities	102,672	41,472
Equity Securities With Readily Determinable Fair Values [Member]
Schedule of Other Securities [Line Items]
Other securities	10,780	10,782
Equity Securities Without Readily Determinable Fair Values [Member]
Schedule of Other Securities [Line Items]
Other securities	$ 359,803	$ 297,504