Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	$ 10,277,662	$ 9,733,478
90 Days or More Past Due and Accruing	24,311	7,804
Loans held for sale	12,887	25,277
Total loans, current	10,228,082	9,698,760
Total loans	10,290,549	9,758,755
Total Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	32,767	39,488
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	609,765	605,682
90 Days or More Past Due and Accruing	1,006	685
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	5,831,384	5,538,968
90 Days or More Past Due and Accruing	14,208	3,093
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,010,344	1,721,378
90 Days or More Past Due and Accruing	2,456	2,840
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	309,313	277,130
90 Days or More Past Due and Accruing	559	627
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	955,644	833,880
90 Days or More Past Due and Accruing	295	51
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,875,740	4,705,088
90 Days or More Past Due and Accruing	13,913	3,042
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,516,856	1,590,320
90 Days or More Past Due and Accruing	6,082	559
Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	28,184	35,742
TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,583	3,746
Current [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	10,215,195	9,673,483
Loans held for sale, current	12,887	25,277
Current [Member] | Total Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	16,447	14,449
Current [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	603,115	599,189
Current [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	5,807,777	5,514,783
Current [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,998,214	1,702,587
Current [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	305,452	273,577
Current [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	955,075	833,755
Current [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,852,702	4,681,028
Current [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,500,637	1,583,347
Current [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	12,189	11,174
Current [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,258	3,275
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	13,262	14,755
30-59 Days Past Due [Member] | Total Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	748	917
30-59 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,571	2,240
30-59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,607	6,377
30-59 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,079	2,331
30-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,288	1,532
30-59 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	134
30-59 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,473	6,377
30-59 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,717	2,275
30-59 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	721	914
30-59 Days Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	27	3
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	10,204	14,005
60-89 Days Past Due [Member] | Total Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	882	691
60-89 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	782	602
60-89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,283	7,728
60-89 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,758	3,254
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	895	1,208
60-89 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	140
60-89 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,143	7,728
60-89 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	3,486	1,213
60-89 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	882	564
60-89 Days Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income		127
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	39,001	31,235
90 Days or More Past Due [Member] | Total Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	14,690	23,431
90 Days or More Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	3,297	3,651
90 Days or More Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	18,717	10,080
90 Days or More Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	8,293	13,206
90 Days or More Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	678	813
90 Days or More Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	295	125
90 Days or More Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	18,422	9,955
90 Days or More Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	8,016	3,485
90 Days or More Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	14,392	23,090
90 Days or More Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	298	341
Total Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	62,467	59,995
Total Past Due [Member] | Total Non-performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	16,320	25,039
Total Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	6,650	6,493
Total Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	23,607	24,185
Total Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	12,130	18,791
Total Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	3,861	3,553
Total Past Due [Member] | Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	569	125
Total Past Due [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	23,038	24,060
Total Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	16,219	6,973
Total Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	15,995	24,568
Total Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	$ 325	$ 471