v3.22.4
Loans (Age Analysis of Past Due Loans, Segregated by Class of Loans) (Detail) - USD ($)
$ in Thousands
Dec. 31, 2022
Dec. 31, 2021
Financing Receivable, Past Due [Line Items]    
Total loans $ 17,154,969 $ 16,336,397
Accruing Loans 90 or More Days Past Due 27,800  
Commercial Portfolio Segment [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 5,674,798 5,364,954
Accruing Loans 90 or More Days Past Due 5,560  
Commercial and Industrial Total Energy Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 925,729 1,077,792
Accruing Loans 90 or More Days Past Due 0  
Paycheck Protection Program [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 34,852 428,882
Accruing Loans 90 or More Days Past Due 13,867  
Commercial Real Estate, Buildings, Land and Other [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 6,706,078 6,272,339
Accruing Loans 90 or More Days Past Due 5,664  
Construction Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 1,477,247 1,304,271
Accruing Loans 90 or More Days Past Due 0  
Total consumer real estate loans [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 1,843,539 1,410,790
Accruing Loans 90 or More Days Past Due 2,398  
Consumer Loan [Member]    
Financing Receivable, Past Due [Line Items]    
Total loans 492,726 477,369
Accruing Loans 90 or More Days Past Due 311  
Financing Receivables, 30 to 89 Days Past Due [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 80,940  
Financing Receivables, 30 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 36,167  
Financing Receivables, 30 to 89 Days Past Due [Member] | Commercial and Industrial Total Energy Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 2,880  
Financing Receivables, 30 to 89 Days Past Due [Member] | Paycheck Protection Program [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 5,321  
Financing Receivables, 30 to 89 Days Past Due [Member] | Commercial Real Estate, Buildings, Land and Other [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 23,561  
Financing Receivables, 30 to 89 Days Past Due [Member] | Construction Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 0  
Financing Receivables, 30 to 89 Days Past Due [Member] | Total consumer real estate loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 7,856 4,877
Financing Receivables, 30 to 89 Days Past Due [Member] | Consumer Loan [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 5,155 4,185
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 43,270  
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 12,853  
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and Industrial Total Energy Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 7,680  
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Paycheck Protection Program [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 13,867  
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate, Buildings, Land and Other [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 5,869  
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Construction Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 0  
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Total consumer real estate loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 2,690 2,513
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 311 1,076
Financial Asset, Past Due    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 124,210  
Financial Asset, Past Due | Commercial Portfolio Segment [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 49,020  
Financial Asset, Past Due | Commercial and Industrial Total Energy Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 10,560  
Financial Asset, Past Due | Paycheck Protection Program [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 19,188  
Financial Asset, Past Due | Commercial Real Estate, Buildings, Land and Other [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 29,430  
Financial Asset, Past Due | Construction Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 0  
Financial Asset, Past Due | Total consumer real estate loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 10,546 7,390
Financial Asset, Past Due | Consumer Loan [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 5,466 5,261
Financial Asset, Not Past Due    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 17,030,759  
Financial Asset, Not Past Due | Commercial Portfolio Segment [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 5,625,778  
Financial Asset, Not Past Due | Commercial and Industrial Total Energy Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 915,169  
Financial Asset, Not Past Due | Paycheck Protection Program [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 15,664  
Financial Asset, Not Past Due | Commercial Real Estate, Buildings, Land and Other [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 6,676,648  
Financial Asset, Not Past Due | Construction Loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,477,247  
Financial Asset, Not Past Due | Total consumer real estate loans [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss 1,832,993 1,403,400
Financial Asset, Not Past Due | Consumer Loan [Member]    
Financing Receivable, Past Due [Line Items]    
Financing Receivable, before Allowance for Credit Loss $ 487,260 $ 472,108