Disclosures About Fair Value of Assets and Liabilities - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Investment securities available for sale	$ 2,296,351	$ 2,344,551
Investment securities held to maturity	2,025,524	2,202,503
Loans held for sale	9,060	11,187
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and due from banks	212,559	167,146
Interest-bearing deposits	136,702	474,154
Investment securities available for sale	16,189	999
Investment securities held to maturity	0	0
Loans held for sale	0	0
Loans, net	0	0
Federal Home Loan Bank stock	0	0
Derivative assets	0	0
Interest receivable	0	0
Liabilities:
Deposits	13,661,769	12,038,992
Borrowings:
Federal funds purchased	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank advances	0	0
Subordinated debentures and other borrowings	0	0
Derivative liabilities	0	0
Interest payable	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Investment securities available for sale	2,271,532	2,338,061
Investment securities held to maturity	2,014,738	2,188,600
Loans held for sale	9,060	11,187
Loans, net	0	0
Federal Home Loan Bank stock	38,111	28,736
Derivative assets	56,299	41,133
Interest receivable	68,728	57,187
Liabilities:
Deposits	893,017	690,089
Borrowings:
Federal funds purchased	100,000
Securities sold under repurchase agreements	186,461	181,572
Federal Home Loan Bank advances	594,508	337,005
Subordinated debentures and other borrowings	139,830	107,892
Derivative liabilities	55,982	41,968
Interest payable	2,978	2,762
Significant Unobservable Inputs (Level 3)
Assets:
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Investment securities available for sale	8,630	5,491
Investment securities held to maturity	10,786	13,903
Loans held for sale	0	0
Loans, net	10,828,993	9,068,319
Federal Home Loan Bank stock	0	0
Derivative assets	0	0
Interest receivable	0	0
Liabilities:
Deposits	0	0
Borrowings:
Federal funds purchased	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank advances	0	0
Subordinated debentures and other borrowings	0	0
Derivative liabilities	0	0
Interest payable	0	0
Carrying Amount
Assets:
Cash and due from banks	212,559	167,146
Interest-bearing deposits	136,702	474,154
Investment securities available for sale	2,296,351	2,344,551
Investment securities held to maturity	2,333,679	2,179,802
Loans held for sale	9,060	11,187
Loans, net	11,171,142	9,046,464
Federal Home Loan Bank stock	38,111	28,736
Derivative assets	56,299	41,133
Interest receivable	68,728	57,187
Liabilities:
Deposits	14,570,869	12,732,577
Borrowings:
Federal funds purchased	100,000
Securities sold under repurchase agreements	186,468	181,577
Federal Home Loan Bank advances	598,865	334,055
Subordinated debentures and other borrowings	151,299	118,618
Derivative liabilities	55,982	41,968
Interest payable	$ 2,978	$ 2,762

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount, before valuation allowance, of financing receivable classified as held-for-sale.

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Fair value portion of other liabilities.

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Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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