Goodwill and Other Intangibles - Changes In Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 123,571	$ 121,226
Accumulated amortization	107,881	106,810
Net carrying amount	15,690	14,416
Core Deposit Intangible Assets [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	50,059	50,059
Accumulated amortization	49,781	49,623
Net carrying amount	278	436
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	73,512	71,167
Accumulated amortization	58,100	57,187
Net carrying amount	$ 15,412	$ 13,980