Fair Value Measurements - Estimated Fair Values and Related Carrying Amounts of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, net	$ 3,109,610	$ 3,135,370
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	603,402	614,092
Interest bearing balances due from banks - time	100	100
Held-to-maturity securities, net	3,658,700	3,726,288
Interest receivable	125,700	122,430
Federal funds purchased and securities sold under agreements to repurchase	51,071	67,969
Other borrowings	1,045,878	972,366
Subordinated notes and debentures	366,255	366,141
Interest payable	63,210	35,618
Carrying Amount \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	4,521,715	4,800,880
Carrying Amount \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	10,863,945	10,997,425
Carrying Amount \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,549,774	6,446,673
Carrying Amount \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	17,102,817	16,620,439
Fair Value Measurements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	603,402	614,092
Interest bearing balances due from banks - time	100	100
Held-to-maturity securities, net	3,109,610	3,135,370
Interest receivable	125,700	122,430
Federal funds purchased and securities sold under agreements to repurchase	51,071	67,969
Other borrowings	1,045,075	970,846
Subordinated notes and debentures	361,885	349,424
Interest payable	63,210	35,618
Fair Value Measurements \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	4,521,715	4,800,880
Fair Value Measurements \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	10,863,945	10,997,425
Fair Value Measurements \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,542,007	6,414,222
Fair Value Measurements \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	16,174,963	15,734,766
Fair Value Measurements \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	603,402	614,092
Interest bearing balances due from banks - time	0	0
Held-to-maturity securities, net	0	0
Interest receivable	0	0
Federal funds purchased and securities sold under agreements to repurchase	0	0
Other borrowings	0	0
Subordinated notes and debentures	0	0
Interest payable	0	0
Fair Value Measurements \| Level 1 \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements \| Level 1 \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements \| Level 1 \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements \| Level 1 \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	0	0
Fair Value Measurements \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing balances due from banks - time	100	100
Held-to-maturity securities, net	3,109,610	3,135,370
Interest receivable	125,700	122,430
Federal funds purchased and securities sold under agreements to repurchase	51,071	67,969
Other borrowings	1,045,075	970,846
Subordinated notes and debentures	361,885	349,424
Interest payable	63,210	35,618
Fair Value Measurements \| Level 2 \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	4,521,715	4,800,880
Fair Value Measurements \| Level 2 \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	10,863,945	10,997,425
Fair Value Measurements \| Level 2 \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements \| Level 2 \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	0	0
Fair Value Measurements \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing balances due from banks - time	0	0
Held-to-maturity securities, net	0	0
Interest receivable	0	0
Federal funds purchased and securities sold under agreements to repurchase	0	0
Other borrowings	0	0
Subordinated notes and debentures	0	0
Interest payable	0	0
Fair Value Measurements \| Level 3 \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements \| Level 3 \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	0	0
Fair Value Measurements \| Level 3 \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,542,007	6,414,222
Fair Value Measurements \| Level 3 \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	$ 16,174,963	$ 15,734,766

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Fair value portion of interest payable on debt, including, but not limited to, trade payables.

+ References

No definition available.

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The fair value of accrued interest receivable.

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No definition available.

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- Definition

The fair value portion of the aggregate of other miscellaneous borrowings owed by the reporting entity as of the balance sheet date.

+ References

No definition available.

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
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- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

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- Definition

Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

+ References

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-10

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