COMMITMENTS AND CONTINGENCIES - Investment holdings schedule (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	$ 137,469		$ 134,035
Qualified Affordable Housing Project Investments, Commitment	71,298		72,511
Amortization Method Qualified Affordable Housing Project Investments, Amortization	3,152	$ 2,244
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(3,092)	(2,316)
Low Income Housing Tax Credits
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	112,653		108,974
Qualified Affordable Housing Project Investments, Commitment	58,641		57,341
Amortization Method Qualified Affordable Housing Project Investments, Amortization	3,048	2,036
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(2,959)	(2,183)
Historic tax credit [Member]
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	2,581		2,581
Qualified Affordable Housing Project Investments, Commitment	56		56
Amortization Method Qualified Affordable Housing Project Investments, Amortization	0	155
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(80)	(80)
New Markets Tax Credit
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	3,660		3,895
Qualified Affordable Housing Project Investments, Commitment	0		0
Amortization Method Qualified Affordable Housing Project Investments, Amortization	104	53
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(53)	(53)
Renewable Energy Program
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	18,575		18,585
Qualified Affordable Housing Project Investments, Commitment	12,601		$ 15,114
Amortization Method Qualified Affordable Housing Project Investments, Amortization	0	0
Affordable Housing Tax Credits and Other Tax Benefits, Amount	$ 0	$ 0

Amount of affordable housing tax credits and other tax benefits recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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Amount of investment in qualified affordable housing projects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
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Amount of amortization expense of investment in qualified affordable housing projects.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
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-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 323
-SubTopic 740
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=116633289&loc=SL49122993-202985

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