LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (portfolio of non-risk-rated loans by class and delinquency status) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial Asset, Not Past Due
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 9,066,075	$ 9,834,851
30 to 59 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,527	10,675
60 to 89 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,142	2,908
90 Days or More Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,019	22,548
Small Balance CRE [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	73,342	56,544
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	80,992	80,090
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	74,079	84,749
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	82,151	78,249
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	67,886	68,791
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	219,229	202,876
Financing Receivable, Revolving	533	2,550
Financing Receivable, before Allowance for Credit Loss	598,212	573,849
Small Balance CRE [Member] | Financial Asset, Not Past Due
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	73,302	56,544
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	80,992	80,090
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	74,079	84,749
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	82,151	77,637
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	67,837	68,791
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	219,117	202,653
Financing Receivable, Revolving	533	2,550
Financing Receivable, before Allowance for Credit Loss	598,011	573,014
Small Balance CRE [Member] | 30 to 59 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	40	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	49	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	89	0
Small Balance CRE [Member] | 60 to 89 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	45
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	0	45
Small Balance CRE [Member] | 90 Days or More Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	567
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	112	223
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	112	790
Small Credit-Scored Business Loans [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	235,695	157,461
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	127,296	145,474
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	109,616	127,691
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	84,666	91,081
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	56,329	48,082
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	69,763	63,948
Financing Receivable, Revolving	108,945	109,714
Financing Receivable, before Allowance for Credit Loss	792,310	743,451
Small Credit-Scored Business Loans [Member] | Financial Asset, Not Past Due
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	235,435	157,161
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	126,959	145,037
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	109,483	126,578
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	84,460	89,734
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	55,940	47,909
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	69,504	63,347
Financing Receivable, Revolving	108,632	109,287
Financing Receivable, before Allowance for Credit Loss	790,413	739,053
Small Credit-Scored Business Loans [Member] | 30 to 59 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	260	129
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	268	62
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	310
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	133	723
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	74	4
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	4	1
Financing Receivable, Revolving	185	230
Financing Receivable, before Allowance for Credit Loss	924	1,459
Small Credit-Scored Business Loans [Member] | 60 to 89 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	98
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	147
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	133	3
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	11	140
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	9	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	248	352
Financing Receivable, Revolving	64	151
Financing Receivable, before Allowance for Credit Loss	465	891
Small Credit-Scored Business Loans [Member] | 90 Days or More Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	73
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	69	228
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	800
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	62	484
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	306	169
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	7	248
Financing Receivable, Revolving	64	46
Financing Receivable, before Allowance for Credit Loss	508	2,048
One- to four-family residential [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	229,473	106,462
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	90,230	90,539
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	56,845	94,738
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	52,311	102,776
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	54,642	60,907
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	198,342	259,353
Financing Receivable, Revolving	1,425	3,164
Financing Receivable, before Allowance for Credit Loss	683,268	717,939
One- to four-family residential [Member] | Financial Asset, Not Past Due
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	229,473	105,411
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	89,634	90,425
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	56,843	92,232
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	51,445	101,491
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	54,007	60,738
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	196,571	254,850
Financing Receivable, Revolving	1,425	3,164
Financing Receivable, before Allowance for Credit Loss	679,398	708,311
One- to four-family residential [Member] | 30 to 59 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	1,051
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	596	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	1,302
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	404	829
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	635	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	683	1,438
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	2,318	4,620
One- to four-family residential [Member] | 60 to 89 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2	19
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	295	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	30	936
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	327	955
One- to four-family residential [Member] | 90 Days or More Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	114
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	1,185
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	167	456
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	169
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,058	2,129
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	1,225	4,053
Home Equity Line of Credit [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	7,331	10,522
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,210	3,131
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,433	2,751
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,986	3,923
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,002	1,658
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,759	2,696
Financing Receivable, Revolving	440,812	467,131
Financing Receivable, before Allowance for Credit Loss	458,533	491,812
Home Equity Line of Credit [Member] | Financial Asset, Not Past Due
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	7,135	10,522
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,210	2,617
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,324	2,553
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,772	3,359
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	1,764	1,372
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,920	2,154
Financing Receivable, Revolving	440,352	466,490
Financing Receivable, before Allowance for Credit Loss	456,477	489,067
Home Equity Line of Credit [Member] | 30 to 59 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	147	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	23	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	37	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	568	50
Financing Receivable, Revolving	210	409
Financing Receivable, before Allowance for Credit Loss	985	459
Home Equity Line of Credit [Member] | 60 to 89 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	49	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	202
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	45	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	83	237
Financing Receivable, Revolving	91	0
Financing Receivable, before Allowance for Credit Loss	268	439
Home Equity Line of Credit [Member] | 90 Days or More Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	312
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	109	198
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	191	564
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	156	286
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	188	255
Financing Receivable, Revolving	159	232
Financing Receivable, before Allowance for Credit Loss	803	1,847
Consumer Loan [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	18,646	22,101
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	12,917	13,412
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	8,701	13,951
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	8,398	11,488
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,160	8,642
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	17,092	18,842
Financing Receivable, Revolving	25,455	25,522
Financing Receivable, before Allowance for Credit Loss	97,369	113,958
Consumer Loan [Member] | Financial Asset, Not Past Due
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	18,640	21,811
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	12,803	13,377
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	8,676	13,936
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	8,242	11,433
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,138	8,575
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	17,055	18,802
Financing Receivable, Revolving	25,336	25,460
Financing Receivable, before Allowance for Credit Loss	96,890	113,394
Consumer Loan [Member] | 30 to 59 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	48
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	114	35
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13	15
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	150	22
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	22	46
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	29	26
Financing Receivable, Revolving	60	44
Financing Receivable, before Allowance for Credit Loss	388	236
Consumer Loan [Member] | 60 to 89 Days Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	6	242
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	2	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0	33
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	21
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	8	14
Financing Receivable, Revolving	59	18
Financing Receivable, before Allowance for Credit Loss	75	328
Consumer Loan [Member] | 90 Days or More Past Due [Member]
Schedule non-risk-rated loans by class and delinquency status [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	10	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	6	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0	0
Financing Receivable, Revolving	0	0
Financing Receivable, before Allowance for Credit Loss	$ 16	$ 0