Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	$ 11,873,167	$ 11,638,461
90 Days or More Past Due and Accruing	5,408	9,638
Loans held for sale	12,472	16,354
Total loans, current	11,839,851	11,604,632
Total loans	11,885,639	11,654,815
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	740,973	734,219
90 Days or More Past Due and Accruing	1,223	1,407
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	6,754,933	6,565,448
90 Days or More Past Due and Accruing	408	1,899
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,469,357	2,438,574
90 Days or More Past Due and Accruing	3,151	2,602
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	224,732	229,561
90 Days or More Past Due and Accruing	491	546
Commercial Real Estate - Land and Construction [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,087,649	1,055,865
Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	5,667,284	5,509,583
90 Days or More Past Due and Accruing	408	1,899
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,683,172	1,670,659
90 Days or More Past Due and Accruing	135	3,184
Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	32,919	26,808
Current [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	11,827,379	11,588,278
Loans held for sale, current	12,472	16,354
Current [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	730,521	724,293
Current [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	6,738,996	6,546,811
Current [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,458,403	2,429,200
Current [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	220,302	223,989
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	1,087,649	1,055,865
Current [Member] | Commercial Real Estate - Improved Property [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	5,651,347	5,490,946
Current [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,679,157	1,663,985
Current [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	11,054	9,138
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	15,226	15,152
30-59 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,869	4,691
30-59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,852	4,416
30-59 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	3,160	1,572
30-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,905	3,833
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	2,852	4,416
30-59 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,440	640
30-59 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,612	1,300
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	5,605	9,729
60-89 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	2,249	1,198
60-89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,226	3,627
60-89 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	478	2,471
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,019	1,178
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	1,226	3,627
60-89 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	633	1,255
60-89 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	704	706
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	24,957	25,302
90 Days or More Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	3,334	4,037
90 Days or More Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	11,859	10,594
90 Days or More Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	7,316	5,331
90 Days or More Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	506	561
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	11,859	10,594
90 Days or More Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	1,942	4,779
90 Days or More Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	19,549	15,664
Total Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	45,788	50,183
Total Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	10,452	9,926
Total Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	15,937	18,637
Total Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	10,954	9,374
Total Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,430	5,572
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	15,937	18,637
Total Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	4,015	6,674
Total Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, net of unearned income	$ 21,865	$ 17,670