Fair Value Measurements - Estimated Fair Values and Related Carrying Amounts of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities, net	$ 3,094,858	$ 3,063,233
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	745,912	682,122
Interest bearing balances due from banks - time	545	795
Held-to-maturity securities, net	3,756,754	3,759,706
Interest receivable	103,431	102,892
Federal funds purchased and securities sold under agreements to repurchase	102,586	160,403
Other borrowings	1,373,339	859,296
Subordinated notes and debentures	366,065	365,989
Interest payable	27,346	16,399
Carrying Amount \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	16,623,687	15,945,169
Carrying Amount \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	5,264,962	6,016,651
Carrying Amount \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	10,866,078	11,762,885
Carrying Amount \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,357,682	4,768,558
Fair Value Measurements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	745,912	682,122
Interest bearing balances due from banks - time	545	795
Held-to-maturity securities, net	3,094,858	3,063,233
Interest receivable	103,431	102,892
Federal funds purchased and securities sold under agreements to repurchase	102,586	160,403
Other borrowings	1,370,261	857,257
Subordinated notes and debentures	359,801	363,578
Interest payable	27,346	16,399
Fair Value Measurements \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	15,928,195	15,573,555
Fair Value Measurements \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	5,264,962	6,016,651
Fair Value Measurements \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	10,866,078	11,762,885
Fair Value Measurements \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	6,293,911	4,696,473
Fair Value Measurements \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	745,912	682,122
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 \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	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 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
Interest bearing balances due from banks - time	545	795
Held-to-maturity securities, net	3,094,858	3,063,233
Interest receivable	103,431	102,892
Federal funds purchased and securities sold under agreements to repurchase	102,586	160,403
Other borrowings	1,370,261	857,257
Subordinated notes and debentures	359,801	363,578
Interest payable	27,346	16,399
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 2 \| Noninterest bearing transaction accounts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	5,264,962	6,016,651
Fair Value Measurements \| Level 2 \| Interest bearing transaction accounts and savings deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	10,866,078	11,762,885
Fair Value Measurements \| Level 2 \| Time deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deposits	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 \| Legacy Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	15,928,195	15,573,555
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	$ 6,293,911	$ 4,696,473

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.

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The fair value of accrued interest receivable.

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

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No definition available.

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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.

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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.

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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.

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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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

No definition available.

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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 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
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-Topic 942
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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://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Publisher FASB
-URI https://asc.fasb.org//310-10/tableOfContent

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