DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019	Apr. 30, 2020
Derivative [Line Items]
Notional Amount	$ 822,929	$ 580,372
Estimated Fair Value Asset (Liability)	(3,453)	(743)
Interest rate swap
Derivative [Line Items]
Notional Amount		50,000	$ 25,000
Designated as hedging instrument \| Cash flow hedges
Derivative [Line Items]
Notional Amount	$ 125,000	100,000
Weighted Average Maturity (in years)	4 years 1 month 6 days
Estimated Fair Value Asset (Liability)	$ (6,835)	(1,311)
Designated as hedging instrument \| Cash flow hedges \| Interest rate cap agreements
Derivative [Line Items]
Notional Amount	$ 125,000	$ 100,000
Weighted Average Maturity (in years)	4 years 1 month 6 days	4 years 7 months 6 days
Estimated Fair Value Asset (Liability)	$ (6,835)	$ (1,311)
Designated as hedging instrument \| Fair value hedges
Derivative [Line Items]
Notional Amount	$ 37,190	37,190
Weighted Average Maturity (in years)	8 years 8 months 12 days
Estimated Fair Value Asset (Liability)	$ 3,445	593
Designated as hedging instrument \| Fair value hedges \| Interest rate swap
Derivative [Line Items]
Notional Amount	$ 37,190	$ 37,190
Weighted Average Maturity (in years)	8 years 8 months 12 days	9 years 7 months 6 days
Estimated Fair Value Asset (Liability)	$ 3,445	$ 593
Hedged Asset, Fair Value Hedge	42,564	39,026
Cumulative amount of fair value hedging adjustment in carrying amount	5,374	523
Designated as hedging instrument \| Economic hedges
Derivative [Line Items]
Notional Amount	633,009	421,434
Estimated Fair Value Asset (Liability)	(87)	(84)
Designated as hedging instrument \| Economic hedges \| Forward sale commitments
Derivative [Line Items]
Notional Amount	$ 47,739	$ 11,228
Weighted Average Maturity (in years)	2 months 12 days	1 month 6 days
Estimated Fair Value Asset (Liability)	$ (87)	$ (84)
Designated as hedging instrument \| Economic hedges \| Customer loan derivative liability \| MNA counterparty
Derivative [Line Items]
Notional Amount	$ 189,244	$ 135,598
Weighted Average Maturity (in years)	7 years 1 month 6 days	7 years 6 months
Estimated Fair Value Asset (Liability)	$ (16,965)	$ (4,669)
Designated as hedging instrument \| Economic hedges \| Customer loan derivative liability \| RPA counterparty
Derivative [Line Items]
Notional Amount	$ 103,391	$ 69,505
Weighted Average Maturity (in years)	7 years 9 months 18 days	8 years 9 months 18 days
Estimated Fair Value Asset (Liability)	$ (11,071)	$ (3,377)
Designated as hedging instrument \| Economic hedges \| Customer loan derivative liability \| Customer
Derivative [Line Items]
Notional Amount	$ 292,635	$ 205,103
Weighted Average Maturity (in years)	7 years 4 months 24 days	8 years 1 month 6 days
Estimated Fair Value Asset (Liability)	$ 28,036	$ 8,046
Not designated as hedging instrument
Derivative [Line Items]
Notional Amount	$ 27,730	21,748
Weighted Average Maturity (in years)	1 month 6 days
Estimated Fair Value Asset (Liability)	$ 24	59
Not designated as hedging instrument \| Interest Rate Lock Commitment
Derivative [Line Items]
Notional Amount	$ 27,730	$ 21,748
Weighted Average Maturity (in years)	1 month 6 days	1 month 6 days
Estimated Fair Value Asset (Liability)	$ 24	$ 59

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

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Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
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Amount of asset hedged in fair value hedging relationship.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Paragraph 4EE
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Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
-Paragraph 4EE
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-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL109999712-113959

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