Loans and Allowance for Credit Losses - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
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	$ 4,598,000	$ 3,370,000	$ 15,824,000	$ 7,099,000
Unfunded commitments related to nonperforming loans	100,000		100,000		$ 100,000
Off balance sheet reserve to nonperforming loans	0		0		0
Total gains or losses included in earnings	0	0	0	0
Recorded investment	47,924,000		47,924,000		35,487,000
Loans with modifications to rate and payment due to reamortization				10,000
Loans and Leases Receivable, Gross	8,901,725,000		8,901,725,000		7,642,143,000
Loans and Leases Receivable, Net of Deferred Income	8,901,725,000		$ 8,901,725,000		7,642,143,000
Forecasted Value, National Unemployment, Percent			3.78%
Financing Receivable, before Allowance for Credit Loss	8,901,725,000		$ 8,901,725,000		7,642,143,000
Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery			13,800,000	5,100,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default		0	0	0
Accrual Loans [Member] [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring					6,400,000
Centric Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	22,000,000		22,000,000
Net Deferred Fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Deferred Income	7,400,000		7,400,000		5,900,000
Unearned Premiums and Discounts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Deferred Income	(27,600,000)		(27,600,000)		(5,400,000)
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	13,713,000		$ 13,713,000		15,896,000
Weighted average [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent			4.59%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent			4.86%
Time and Demand Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			$ 7,424,000
Loans and Leases Receivable, Gross	1,189,604,000		1,189,604,000		1,023,824,000
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs			0
Loans and Leases Receivable, Gross	537,565,000		537,565,000		431,151,000
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	1,762,000	852,000	9,102,000	1,836,000
Loans and Leases Receivable, Gross	1,496,021,000		1,496,021,000		1,211,706,000
Loans and Leases Receivable, Net of Deferred Income	1,496,021,000		1,496,021,000		1,211,706,000
Financing Receivable, before Allowance for Credit Loss	1,496,021,000		1,496,021,000		1,211,706,000
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	2,112,000		2,112,000		1,233,000
Commercial, financial, agricultural and other [Member] | Time and Demand Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	954,000	321,000	7,424,000	604,000
Loans and Leases Receivable, Gross	1,189,604,000		1,189,604,000		1,023,824,000
Loans and Leases Receivable, Net of Deferred Income	1,189,604,000		1,189,604,000		1,023,824,000
Loans And Leases Receivable, Paycheck Protection Program	900,000		900,000		4,300,000
Financing Receivable, before Allowance for Credit Loss	1,189,604,000		1,189,604,000		1,023,824,000
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	1,630,000		1,630,000		1,121,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	172,000	1,335,000	1,689,000	1,887,000
Loans and Leases Receivable, Gross	3,050,084,000		3,050,084,000		2,425,012,000
Loans and Leases Receivable, Net of Deferred Income	3,050,084,000		3,050,084,000		2,425,012,000
Financing Receivable, before Allowance for Credit Loss	3,050,084,000		3,050,084,000		2,425,012,000
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	2,436,000		2,436,000		7,870,000
Commercial Real Estate [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Charge-offs	0	$ 0	0	411,000
Loans and Leases Receivable, Gross	537,565,000		537,565,000		431,151,000
Loans and Leases Receivable, Net of Deferred Income	537,565,000		537,565,000		431,151,000
Financing Receivable, before Allowance for Credit Loss	537,565,000		537,565,000		431,151,000
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	117,000		$ 117,000		202,000
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