Loans and the Allowance for Credit Losses - Summary of Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	$ 121,622	$ 185,827
Allowance for credit losses - loan commitments, beginning balance	7,775	9,514
Total beginning allowance for credit losses - loans and loan commitments	129,397	195,341
Provision for loan losses	(4,190)	(45,138)
Provision for loan commitments	(57)	(3,748)
Total provision for credit losses - loans and loan commitments	(4,247)	(48,886)
Charge-offs	(3,452)	(3,557)
Recoveries	3,423	3,598
Net (charge-offs) recoveries	(29)	41
Allowance for credit losses - loans, ending balance	117,403	140,730
Allowance for credit losses - loan commitments, ending balance	7,718	5,766
Total ending allowance for credit losses - loans and loan commitments	125,121	146,496
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	26,875	37,850
Allowance for credit losses - loan commitments, beginning balance	1,497	1,275
Total beginning allowance for credit losses - loans and loan commitments	28,372	39,125
Provision for loan losses	1,097	(8,090)
Provision for loan commitments	(1,288)	334
Total provision for credit losses - loans and loan commitments	(191)	(8,424)
Charge-offs	(355)	(814)
Recoveries	551	518
Net (charge-offs) recoveries	196	(296)
Allowance for credit losses - loans, ending balance	28,168	29,464
Allowance for credit losses - loan commitments, ending balance	209	941
Total ending allowance for credit losses - loans and loan commitments	28,377	30,405
Deposit Overdrafts [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	2,220	639
Total beginning allowance for credit losses - loans and loan commitments	2,220	639
Provision for loan losses	(58)	582
Total provision for credit losses - loans and loan commitments	(58)	582
Charge-offs	(776)	(365)
Recoveries	173	200
Net (charge-offs) recoveries	(603)	(165)
Allowance for credit losses - loans, ending balance	1,559	1,056
Total ending allowance for credit losses - loans and loan commitments	1,559	1,056
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	7,310	10,841
Allowance for credit losses - loan commitments, beginning balance	4,180	6,508
Total beginning allowance for credit losses - loans and loan commitments	11,490	17,349
Provision for loan losses	845	(4,740)
Provision for loan commitments	696	(2,929)
Total provision for credit losses - loans and loan commitments	1,541	(7,669)
Charge-offs	(73)	(22)
Recoveries	25	110
Net (charge-offs) recoveries	(48)	88
Allowance for credit losses - loans, ending balance	8,107	6,189
Allowance for credit losses - loan commitments, ending balance	4,876	3,579
Total ending allowance for credit losses - loans and loan commitments	12,983	9,768
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	65,355	110,652
Allowance for credit losses - loan commitments, beginning balance	201	712
Total beginning allowance for credit losses - loans and loan commitments	65,556	111,364
Provision for loan losses	(6,401)	(25,672)
Provision for loan commitments	(201)	(618)
Total provision for credit losses - loans and loan commitments	(6,602)	(26,290)
Charge-offs	(137)	(235)
Recoveries	740	646
Net (charge-offs) recoveries	603	411
Allowance for credit losses - loans, ending balance	59,557	85,391
Allowance for credit losses - loan commitments, ending balance		94
Total ending allowance for credit losses - loans and loan commitments	59,557	85,485
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	15,401	17,851
Allowance for credit losses - loan commitments, beginning balance	1,576	955
Total beginning allowance for credit losses - loans and loan commitments	16,977	18,806
Provision for loan losses	(491)	(4,535)
Provision for loan commitments	582	(111)
Total provision for credit losses - loans and loan commitments	91	(4,424)
Charge-offs	(243)	(441)
Recoveries	264	742
Net (charge-offs) recoveries	21	301
Allowance for credit losses - loans, ending balance	14,931	13,617
Allowance for credit losses - loan commitments, ending balance	2,158	1,066
Total ending allowance for credit losses - loans and loan commitments	17,089	14,683
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	3,737	6,507
Allowance for credit losses - loan commitments, beginning balance	272	19
Total beginning allowance for credit losses - loans and loan commitments	4,009	6,526
Provision for loan losses	780	(1,964)
Provision for loan commitments	140	17
Total provision for credit losses - loans and loan commitments	920	(1,947)
Charge-offs	(1,690)	(1,406)
Recoveries	1,477	1,042
Net (charge-offs) recoveries	(213)	(364)
Allowance for credit losses - loans, ending balance	4,304	4,179
Allowance for credit losses - loan commitments, ending balance	412	36
Total ending allowance for credit losses - loans and loan commitments	4,716	4,215
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - loans, beginning balance	724	1,487
Allowance for credit losses - loan commitments, beginning balance	49	45
Total beginning allowance for credit losses - loans and loan commitments	773	1,532
Provision for loan losses	38	(719)
Provision for loan commitments	14	5
Total provision for credit losses - loans and loan commitments	52	(714)
Charge-offs	(178)	(274)
Recoveries	193	340
Net (charge-offs) recoveries	15	66
Allowance for credit losses - loans, ending balance	777	834
Allowance for credit losses - loan commitments, ending balance	63	50
Total ending allowance for credit losses - loans and loan commitments	$ 840	$ 884