v3.26.1
Loans and the Allowance for Credit Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans individually evaluated for impairment $ 33,176 $ 27,908    
Allowance for loans collectively evaluated for impairment 184,599 190,841    
Allowance for loan commitments 7,740 6,950 $ 6,168 $ 6,120
Total allowance for credit losses - loans and commitments 225,515 225,699 230,034 144,886
Individually evaluated for credit loss 79,492 48,975    
Collectively-evaluated for credit losses 19,399,474 19,177,457    
Total loans 19,478,966 19,226,432    
Commercial and Industrial [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans individually evaluated for impairment 6,965 6,918    
Allowance for loans collectively evaluated for impairment 63,710 58,014    
Allowance for loan commitments 463 552    
Total allowance for credit losses - loans and commitments 71,138 65,484 63,937 42,398
Individually evaluated for credit loss 6,965 6,965    
Collectively-evaluated for credit losses 2,942,898 2,856,928    
Total loans 2,949,863 2,863,893    
Deposit Overdraft [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans collectively evaluated for impairment 1,470 1,855    
Total allowance for credit losses - loans and commitments 1,470 1,855 2,321 1,713
Commercial Real Estate [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Total loans 11,093,370 10,938,834    
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans individually evaluated for impairment 702      
Allowance for loans collectively evaluated for impairment 8,594 10,707    
Allowance for loan commitments 6,175 5,499 5,359 5,105
Total allowance for credit losses - loans and commitments 15,471 16,206 16,275 13,516
Individually evaluated for credit loss 12,210      
Collectively-evaluated for credit losses 1,493,282 1,783,637    
Total loans 1,505,492 1,783,637    
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans individually evaluated for impairment 25,509 20,990    
Allowance for loans collectively evaluated for impairment 69,155 75,724    
Allowance for loan commitments 111      
Total allowance for credit losses - loans and commitments 94,775 96,714 99,244 59,828
Individually evaluated for credit loss 60,317 42,010    
Collectively-evaluated for credit losses 9,527,561 9,113,187    
Total loans 9,587,878 9,155,197    
Residential Real Estate [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans collectively evaluated for impairment 32,773 33,416    
Allowance for loan commitments 967 890 809 1,015
Total allowance for credit losses - loans and commitments 33,740 34,306 35,323 22,805
Collectively-evaluated for credit losses 3,939,813 3,938,585    
Total loans 3,939,813 3,938,585    
Consumer [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans collectively evaluated for impairment 6,591 8,742    
Allowance for loan commitments 24 9 0  
Total allowance for credit losses - loans and commitments 6,615 8,751 10,717 3,391
Collectively-evaluated for credit losses 304,111 355,726    
Total loans 304,111 355,726    
Home Equity [Member]        
Financing Receivable, Allowance for Credit Losses [Line Items]        
Allowance for loans collectively evaluated for impairment 2,306 2,383    
Total allowance for credit losses - loans and commitments 2,306 2,383 $ 2,217 $ 1,235
Collectively-evaluated for credit losses 1,191,809 1,129,394    
Total loans $ 1,191,809 $ 1,129,394