INVESTMENT SECURITIES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Trading gain (losses) recorded in servicing income	$ 0.6	$ (0.7)
Tax exempt interest income on available-for-sale securities	$ 2.8	$ 2.7
Mortgage Backed Securities and Collateralized Mortgage Obligations
Debt Securities, Available-for-sale [Line Items]
Weighted average yield	3.15%		3.08%
US Treasury Notes Securities \| Not Designated as Hedging Instrument, Economic Hedge
Debt Securities, Available-for-sale [Line Items]
Trading securities	$ 62.0		$ 19.0

Available for sale securities debt maturities without single maturity date weighted average yield.

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- Definition

Amount of unrealized and realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 14
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27476-111563

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- Definition

Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities exempt from state, federal and other income tax.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2)
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph (a)

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-Name Regulation S-K (SK)
-Number 229
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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

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562

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-Name Accounting Standards Codification
-Topic 320
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section 45
-Paragraph 1
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-URI https://asc.fasb.org/extlink&oid=124098289&loc=d3e6676-107765

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
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-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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