Securities - Schedule of Other Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule of Other Securities [Line Items]
Other securities	$ 473,434	$ 492,935
FRB and FHLB stock [Member]
Schedule of Other Securities [Line Items]
Other securities	87,672	87,672
Equity Securities With Readily Determinable Fair Values [Member]
Schedule of Other Securities [Line Items]
Other securities	11,292	11,228
Equity Securities Without Readily Determinable Fair Values [Member]
Schedule of Other Securities [Line Items]
Other securities	$ 374,470	$ 394,035