Fair Value Measurements - Estimated Fair Values and Related Carrying Amounts of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, net	$ 2,929,625	$ 2,949,951
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	634,286	687,377
Interest bearing balances due from banks - time	100	100
Held-to-maturity securities, net	3,615,556	3,636,636
Interest receivable	117,398	123,243
Federal funds purchased and securities sold under agreements to repurchase	50,133	37,109
Other borrowings	884,863	745,372
Subordinated notes and debentures	366,331	366,293
Interest payable	52,636	67,111
Carrying Amount \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	4,455,255	4,460,517
Carrying Amount \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	11,265,554	10,982,022
Carrying Amount \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	5,963,811	6,443,211
Carrying Amount \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	16,841,910	16,770,918
Fair Value Measurements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	634,286	687,377
Interest bearing balances due from banks - time	100	100
Held-to-maturity securities, net	2,929,625	2,949,951
Interest receivable	117,398	123,243
Federal funds purchased and securities sold under agreements to repurchase	50,133	37,109
Other borrowings	883,754	743,940
Subordinated notes and debentures	365,081	361,332
Interest payable	52,636	67,111
Fair Value Measurements \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	4,455,255	4,460,517
Fair Value Measurements \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	11,265,554	10,982,022
Fair Value Measurements \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	5,949,775	6,429,309
Fair Value Measurements \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	16,266,425	16,153,128
Fair Value Measurements \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	634,286	687,377
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	2,929,625	2,949,951
Interest receivable	117,398	123,243
Federal funds purchased and securities sold under agreements to repurchase	50,133	37,109
Other borrowings	883,754	743,940
Subordinated notes and debentures	365,081	361,332
Interest payable	52,636	67,111
Fair Value Measurements \| Level 2 \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	4,455,255	4,460,517
Fair Value Measurements \| Level 2 \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	11,265,554	10,982,022
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	5,949,775	6,429,309
Fair Value Measurements \| Level 3 \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	$ 16,266,425	$ 16,153,128

Represents the fair value portion of interest bearing balances due from banks - time.

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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
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-10

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