COMMITMENTS AND CONTINGENCIES - Investment holdings schedule (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	$ 181,262		$ 181,262		$ 158,440
Qualified Affordable Housing Project Investments, Commitment	101,915		101,915		84,334
Amortization Method Qualified Affordable Housing Project Investments, Amortization	3,559	$ 20,423	10,831	$ 26,730
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(3,567)	(21,771)	(10,808)	(27,829)
Low Income Housing Tax Credits
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	135,187		135,187		126,537
Qualified Affordable Housing Project Investments, Commitment	74,149		74,149		70,690
Amortization Method Qualified Affordable Housing Project Investments, Amortization	3,455	3,211	10,520	9,311
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(3,434)	(2,757)	(10,411)	(8,551)
Historic tax credit [Member]
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	19,798		19,798		17,108
Qualified Affordable Housing Project Investments, Commitment	14,784		14,784		11,955
Amortization Method Qualified Affordable Housing Project Investments, Amortization	0	0	0	0
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(80)	(80)	(239)	(239)
New Markets Tax Credit
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	2,192		2,192		2,944
Qualified Affordable Housing Project Investments, Commitment	0		0		0
Amortization Method Qualified Affordable Housing Project Investments, Amortization	104	104	311	311
Affordable Housing Tax Credits and Other Tax Benefits, Amount	(53)	(53)	(158)	(158)
Renewable Energy Program
Summary of Investment Holdings [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	24,085		24,085		11,851
Qualified Affordable Housing Project Investments, Commitment	12,982		12,982		$ 1,689
Amortization Method Qualified Affordable Housing Project Investments, Amortization	0	17,108	0	17,108
Affordable Housing Tax Credits and Other Tax Benefits, Amount	$ 0	$ (18,881)	$ 0	$ (18,881)