Goodwill and Other Intangibles - Changes In Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 123,571	$ 121,226
Accumulated amortization	110,198	106,810
Net carrying amount	13,373	14,416
Core Deposit Intangible Assets [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	52,404	50,059
Accumulated amortization	50,361	49,623
Net carrying amount	2,043	436
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	71,167	71,167
Accumulated amortization	59,837	57,187
Net carrying amount	$ 11,330	$ 13,980