Investment Securities - Securities Pledged as Collateral (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Investment Securities
Carrying amount of the securities pledged to collateralize repurchase agreements	$ 7,344,483	$ 8,189,780
Asset Pledged as Collateral [Member]
Investment Securities
Investment securities market value	2,500,000	2,700,000
Carrying amount of the securities pledged to collateralize repurchase agreements	2,800,000	2,900,000
Asset Pledged as Collateral [Member] \| Public Funds Deposits
Investment Securities
Carrying amount of the securities pledged to collateralize repurchase agreements	2,000,000	2,100,000
Asset Pledged as Collateral [Member] \| FHLB Advances
Investment Securities
Carrying amount of the securities pledged to collateralize repurchase agreements	651,900	630,000
Asset Pledged as Collateral [Member] \| Interest rate swap
Investment Securities
Carrying amount of the securities pledged to collateralize repurchase agreements	$ 133,500	$ 149,200

Fair value of investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-5A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

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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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481444/860-30-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1

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- Definition

Sum of the carrying amounts as of the balance sheet date of all investments.

+ 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)(h))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

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