Loans and Allowance for Credit Losses - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due			90 days
Default Status Of TDRs After Number Of Days Past Due			90 days
Charge-offs	$ 4,426,000	$ 5,469,000	$ 12,436,000	$ 11,032,000	$ 35,428,000
Unfunded commitments related to nonperforming loans	200,000		200,000		300,000
Off balance sheet reserve to nonperforming loans	0		0		0
Total gains or losses included in earnings			$ 0	0
Forecasted Value, National Unemployment, Percent			4.21%
Financing Receivable, before Allowance for Credit Loss	9,570,815,000		$ 9,570,815,000		8,983,754,000
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery			5,900,000	8,700,000
Post- Modification Outstanding Recorded Investment	32,357,000	10,113,000	36,138,000	11,810,000
Net Deferred Fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned Deferred (Fees) Costs on Loans	17,300,000		17,300,000		14,700,000
Unearned Premiums and Discounts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned Deferred (Fees) Costs on Loans	(26,400,000)		(26,400,000)		(18,900,000)
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	13,488,000		13,488,000		14,673,000
Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,452,894,000		$ 9,452,894,000		8,900,116,000
Weighted average [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent			5.02%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent			5.42%
Time and Demand Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			$ 3,339,000		11,131,000
Financing Receivable, before Allowance for Credit Loss	1,255,560,000		1,255,560,000		1,133,595,000
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			0		0
Financing Receivable, before Allowance for Credit Loss	644,970,000		644,970,000		597,145,000
Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			875,000		7,138,000
Financing Receivable, before Allowance for Credit Loss	1,948,160,000		1,948,160,000		1,804,950,000
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	1,403,000	2,588,000	5,422,000	5,250,000
Financing Receivable, before Allowance for Credit Loss	1,955,333,000		1,955,333,000		1,677,989,000
Post- Modification Outstanding Recorded Investment	32,192,000	245,000	32,192,000	1,471,000
Commercial, financial, agricultural and other [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,386,000		3,386,000		2,379,000
Commercial, financial, agricultural and other [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,897,197,000		1,897,197,000		1,659,053,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	363,000	1,612,000	3,339,000	3,377,000
Financing Receivable, before Allowance for Credit Loss	1,255,560,000		1,255,560,000		1,133,595,000
Post- Modification Outstanding Recorded Investment	31,880,000	245,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,024,000		3,024,000		649,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,199,339,000		1,199,339,000		1,117,613,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	624,000	341,000	2,088,000	624,000
Financing Receivable, before Allowance for Credit Loss	3,366,267,000		3,366,267,000		3,124,704,000
Post- Modification Outstanding Recorded Investment		9,675,000	3,201,000	9,827,000
Commercial Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,581,000		1,581,000		1,597,000
Commercial Real Estate [Member] | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,333,457,000		3,333,457,000		3,089,905,000
Commercial Real Estate [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	0	0	0	0
Financing Receivable, before Allowance for Credit Loss	644,970,000		644,970,000		597,145,000
Commercial Real Estate [Member] | Multifamily | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	0		0		212,000
Commercial Real Estate [Member] | Multifamily | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	644,009,000		644,009,000		596,913,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	1,000	$ 187,000	875,000	470,000
Financing Receivable, before Allowance for Credit Loss	1,948,160,000		1,948,160,000		1,804,950,000
Post- Modification Outstanding Recorded Investment			3,201,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	361,000		361,000		72,000
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate | Financial Asset, Not Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,929,310,000		$ 1,929,310,000		1,779,586,000
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due			150 days
Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Held for sale, Amount	$ 0		$ 0		$ 0
Loans and Leases Receivable, Gain (Loss) on Sales, Net			$ 0	$ 0