Loans and Allowance for Credit Losses - Outstanding Balances of Loan (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	$ 9,508,039	$ 8,983,754
Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,226,054	1,133,595
Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	11,408	11,718
Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,631,019	1,670,547
Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	729,266	671,156
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	594,790	597,145
Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,834,016	1,804,950
Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	753,303	722,609
Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,387,195	1,280,645
Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	9,496	9,865
Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	61,179	65,464
Equipment Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	693,265	427,320
Time and Demand Loans Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	114,262	105,356
Construction Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	415,536	475,367
Construction Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	47,250	8,017
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	2,044,989	1,677,989
Commercial, financial, agricultural and other [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,226,054	1,133,595
Commercial, financial, agricultural and other [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	11,408	11,718
Commercial, financial, agricultural and other [Member] | Equipment Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	693,265	427,320
Commercial, financial, agricultural and other [Member] | Time and Demand Loans Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	114,262	105,356
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	462,786	483,384
Real Estate Construction [Member] | Construction Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	415,536	475,367
Real Estate Construction [Member] | Construction Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	47,250	8,017
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	2,360,285	2,341,703
Residential Real Estate [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,631,019	1,670,547
Residential Real Estate [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	729,266	671,156
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,182,109	3,124,704
Commercial real estate [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	594,790	597,145
Commercial real estate [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,834,016	1,804,950
Commercial real estate [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	753,303	722,609
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,457,870	1,355,974
Loans To Individuals [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,387,195	1,280,645
Loans To Individuals [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	9,496	9,865
Loans To Individuals [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	$ 61,179	$ 65,464