LOANS RECEIVABLE, NET - Quality Indicator, Prior Year (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
2023	$ 108,386		$ 567,798
2022	585,357		1,183,947
2021	1,157,012		777,257
2020	774,619		512,024
2019 & Prior	1,640,739		1,187,173
Revolving loans	157,667		183,120
Revolving Loans Converted to Term	0		0
Total	4,423,780		4,411,319
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total	2,462	$ 3,010
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	108,386		567,793
2022	585,327		1,179,430
2021	1,154,205		758,419
2020	740,954		500,122
2019 & Prior	1,592,520		1,149,363
Revolving loans	142,998		146,660
Revolving Loans Converted to Term	0		0
Total	4,324,390		4,301,787
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		2
2022	253		1,525
2021	321		3,034
2020	1,298		2,095
2019 & Prior	590		9,402
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	2,462		16,058
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	86		16,692
2020	13,750		3,975
2019 & Prior	16,815		13,104
Revolving loans	1,406		4,222
Revolving Loans Converted to Term	0		0
Total	32,057		37,993
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		5
2022	30		4,517
2021	2,721		2,146
2020	19,915		7,927
2019 & Prior	30,313		24,706
Revolving loans	13,202		32,238
Revolving Loans Converted to Term	0		0
Total	66,181		71,539
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	1,091		0
Revolving loans	61		0
Revolving Loans Converted to Term	0		0
Total	1,152		0
Commercial portfolio | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2023	24,254		130,568
2022	151,201		221,272
2021	196,285		209,374
2020	224,040		127,084
2019 & Prior	280,809		159,403
Revolving loans	137,495		163,297
Revolving Loans Converted to Term	0		0
Total	1,014,084		1,010,998
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		0
2022	250		0
2021	150		0
2020	0		0
2019 & Prior	0		1,726
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	400		1,726
Commercial portfolio | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	24,254		130,568
2022	151,201		220,552
2021	195,629		192,682
2020	192,446		117,966
2019 & Prior	254,474		141,542
Revolving loans	133,950		138,003
Revolving Loans Converted to Term	0		0
Total	951,954		941,313
Commercial portfolio | Commercial and industrial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	86		16,692
2020	13,750		3,975
2019 & Prior	4,695		934
Revolving loans	1,406		4,222
Revolving Loans Converted to Term	0		0
Total	19,937		25,823
Commercial portfolio | Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		720
2021	570		0
2020	17,844		5,143
2019 & Prior	20,549		16,927
Revolving loans	2,078		21,072
Revolving Loans Converted to Term	0		0
Total	41,041		43,862
Commercial portfolio | Commercial and industrial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	1,091		0
Revolving loans	61		0
Revolving Loans Converted to Term	0		0
Total	1,152		0
Commercial portfolio | Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
2023	50,247		193,827
2022	223,462		382,652
2021	364,213		45,287
2020	44,108		138,131
2019 & Prior	493,435		388,221
Revolving loans	2		2
Revolving Loans Converted to Term	0		0
Total	1,175,467		1,148,120
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		2,367
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0	1,127	2,367
Commercial portfolio | Multifamily | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	50,247		193,827
2022	223,462		382,652
2021	364,213		45,287
2020	44,108		138,131
2019 & Prior	482,807		377,554
Revolving loans	2		2
Revolving Loans Converted to Term	0		0
Total	1,164,839		1,137,453
Commercial portfolio | Multifamily | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	8,347		8,373
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	8,347		8,373
Commercial portfolio | Multifamily | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	2,281		2,294
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	2,281		2,294
Commercial portfolio | Multifamily | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Commercial portfolio | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	15,958		73,089
2022	42,021		42,824
2021	59,599		48,624
2020	48,314		38,336
2019 & Prior	183,859		147,103
Revolving loans	3,847		3,456
Revolving Loans Converted to Term	0		0
Total	353,598		353,432
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0	0	0
Commercial portfolio | Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	15,958		73,089
2022	42,021		42,824
2021	59,599		48,624
2020	48,314		36,478
2019 & Prior	175,732		140,674
Revolving loans	3,847		3,456
Revolving Loans Converted to Term	0		0
Total	345,471		345,145
Commercial portfolio | Commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	3,773		3,797
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	3,773		3,797
Commercial portfolio | Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		1,858
2019 & Prior	4,354		2,632
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	4,354		4,490
Commercial portfolio | Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Commercial portfolio | Construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	6,943		7,261
Revolving loans	16,323		16,365
Revolving Loans Converted to Term	0		0
Total	23,266		23,626
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		4,664
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0	0	4,664
Commercial portfolio | Construction and land development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	6,943		7,261
Revolving loans	5,199		5,199
Revolving Loans Converted to Term	0		0
Total	12,142		12,460
Commercial portfolio | Construction and land development | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Commercial portfolio | Construction and land development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	11,124		11,166
Revolving Loans Converted to Term	0		0
Total	11,124		11,166
Commercial portfolio | Construction and land development | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Commercial portfolio | Residential real estate lending
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total	160
Retail portfolio | Residential real estate lending
Financing Receivable, Credit Quality Indicator [Line Items]
2023	17,544		137,167
2022	136,060		417,194
2021	420,051		329,955
2020	317,818		135,194
2019 & Prior	527,848		406,086
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	1,419,321		1,425,596
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	160		65
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	160	58	65
Retail portfolio | Residential real estate lending | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	17,544		137,167
2022	136,060		413,962
2021	419,329		328,952
2020	316,789		134,795
2019 & Prior	525,799		403,508
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	1,415,521		1,418,384
Retail portfolio | Residential real estate lending | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Retail portfolio | Residential real estate lending | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		3,232
2021	722		1,003
2020	1,029		399
2019 & Prior	2,049		2,578
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	3,800		7,212
Retail portfolio | Residential real estate lending | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Retail portfolio | Consumer solar
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		30,412
2022	30,551		105,162
2021	102,443		132,088
2020	128,659		73,279
2019 & Prior	136,848		67,319
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	398,501		408,260
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		0
2022	0		1,525
2021	171		3,034
2020	1,298		2,095
2019 & Prior	337		312
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	1,806	1,807	6,966
Retail portfolio | Consumer solar | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		30,412
2022	30,527		104,633
2021	101,034		131,008
2020	127,718		72,752
2019 & Prior	135,835		67,044
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	395,114		405,849
Retail portfolio | Consumer solar | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Retail portfolio | Consumer solar | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	24		529
2021	1,409		1,080
2020	941		527
2019 & Prior	1,013		275
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	3,387		2,411
Retail portfolio | Consumer solar | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Retail portfolio | Consumer and Other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	383		2,735
2022	2,062		14,843
2021	14,421		11,929
2020	11,680		0
2019 & Prior	10,997		11,780
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	39,543		41,287
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
2023	0		2
2022	3		0
2021	0		0
2020	0		0
2019 & Prior	93		268
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	96	$ 18	270
Retail portfolio | Consumer and Other | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	383		2,730
2022	2,056		14,807
2021	14,401		11,866
2020	11,579		0
2019 & Prior	10,930		11,780
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	39,349		41,183
Retail portfolio | Consumer and Other | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	0		0
Retail portfolio | Consumer and Other | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		5
2022	6		36
2021	20		63
2020	101		0
2019 & Prior	67		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	194		104
Retail portfolio | Consumer and Other | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0		0
2022	0		0
2021	0		0
2020	0		0
2019 & Prior	0		0
Revolving loans	0		0
Revolving Loans Converted to Term	0		0
Total	$ 0		$ 0