LOANS AND ALLOWANCE FOR CREDIT LOSSES - Financing Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Balance at beginning of period			$ 60,754
Balance at end of period	$ 61,058		61,058
Allowance for credit losses
Balance at beginning of period	60,797	$ 67,702	60,754	$ 67,338
Provision (credit) charged to expense		(1,000)		(700)
Losses charged off	(433)	(899)	(870)	(1,554)
Recoveries	694	799	1,174	1,518
Balance at end of period	61,058	66,602	61,058	66,602
CECL adoption | Allowance for credit losses
Balance at beginning of period				11,595
Before CECL adoption | Allowance for credit losses
Balance at beginning of period				55,743
Loans Receivable | Allowance for unfunded commitment
Balance at beginning of period	9,436	8,016	9,629	8,690
Provision (credit) charged to expense	2,223	(307)	2,030	(981)
Balance at end of period	11,659	7,709	11,659	7,709
Loans Receivable | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				8,690
Commercial Real Estate | Allowance for unfunded commitment
Balance at beginning of period	423	457	367	354
Provision (credit) charged to expense	78	(40)	134	63
Balance at end of period	501	417	501	417
Commercial Real Estate | Allowance for credit losses
Balance at beginning of period	28,604	31,500	28,604	31,176
Provision (credit) charged to expense		(1,000)		(700)
Recoveries		7		31
Balance at end of period	28,604	30,507	28,604	30,507
Commercial Real Estate | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				354
Commercial Real Estate | CECL adoption | Allowance for credit losses
Balance at beginning of period				(2,531)
Commercial Real Estate | Before CECL adoption | Allowance for credit losses
Balance at beginning of period				33,707
Commercial construction | Allowance for unfunded commitment
Balance at beginning of period	1,069	510	908	910
Provision (credit) charged to expense	(374)	(156)	(213)	(556)
Balance at end of period	695	354	695	354
Commercial construction | Allowance for credit losses
Balance at beginning of period	2,797	2,366	2,797	2,356
Losses charged off		(154)		(154)
Recoveries		3		13
Balance at end of period	2,797	2,215	2,797	2,215
Commercial construction | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				910
Commercial construction | CECL adoption | Allowance for credit losses
Balance at beginning of period				(1,165)
Commercial construction | Before CECL adoption | Allowance for credit losses
Balance at beginning of period				3,521
One- to four-family residential construction | Allowance for unfunded commitment
Balance at beginning of period	1,199	957	687	917
Provision (credit) charged to expense	(61)	(197)	451	(157)
Balance at end of period	1,138	760	1,138	760
One- to four-family residential construction | Allowance for credit losses
Balance at beginning of period	9,382	9,101	9,364	9,069
Losses charged off	(2)	(136)	(38)	(142)
Recoveries	54	244	108	282
Balance at end of period	9,434	9,209	9,434	9,209
One- to four-family residential construction | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				917
One- to four-family residential construction | CECL adoption | Allowance for credit losses
Balance at beginning of period				4,533
One- to four-family residential construction | Before CECL adoption | Allowance for credit losses
Balance at beginning of period				4,536
Other residential | Allowance for unfunded commitment
Balance at beginning of period	4,700	4,814	5,703	5,227
Provision (credit) charged to expense	2,719	158	1,716	(255)
Balance at end of period	7,419	4,972	7,419	4,972
Other residential | Allowance for credit losses
Balance at beginning of period	10,502	15,299	10,502	15,207
Recoveries	110		110	92
Balance at end of period	10,612	15,299	10,612	15,299
Other residential | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				5,227
Other residential | CECL adoption | Allowance for credit losses
Balance at beginning of period				5,832
Other residential | Before CECL adoption | Allowance for credit losses
Balance at beginning of period				9,375
Commercial business | Allowance for unfunded commitment
Balance at beginning of period	1,618	956	1,582	935
Provision (credit) charged to expense	(212)	(135)	(176)	(114)
Balance at end of period	1,406	821	1,406	821
Commercial business | Allowance for credit losses
Balance at beginning of period	4,162	3,936	4,142	3,889
Losses charged off		(57)		(57)
Recoveries	203	53	223	100
Balance at end of period	4,365	3,932	4,365	3,932
Commercial business | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				935
Commercial business | CECL adoption | Allowance for credit losses
Balance at beginning of period				1,499
Commercial business | Before CECL adoption | Allowance for credit losses
Balance at beginning of period				2,390
Consumer | Allowance for unfunded commitment
Balance at beginning of period	427	322	382	347
Provision (credit) charged to expense	73	63	118	38
Balance at end of period	500	385	500	385
Consumer | Allowance for credit losses
Balance at beginning of period	5,350	5,500	5,345	5,641
Losses charged off	(431)	(552)	(832)	(1,201)
Recoveries	327	492	733	1,000
Balance at end of period	$ 5,246	$ 5,440	$ 5,246	5,440
Consumer | CECL adoption | Allowance for unfunded commitment
Balance at beginning of period				347
Consumer | CECL adoption | Allowance for credit losses
Balance at beginning of period				3,427
Consumer | Before CECL adoption | Allowance for credit losses
Balance at beginning of period				$ 2,214