LOANS RECEIVABLE AND THE ALLOWANCE FOR CREDIT LOSSES (Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	$ 144,680	$ 128,702	$ 141,465	$ 132,099
Provision for credit losses	2,943	6,347	7,276	2,115
Recoveries	806	1,374	2,257	2,955
Charge-offs	(1,469)	(505)	(4,038)	(1,251)
Allowance for loan losses, Ending balance	146,960	135,918	146,960	135,918
Commercial Real Estate
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	43,636	46,373	44,086	52,995
Provision for credit losses	210	(2,096)	(498)	(8,932)
Recoveries	170	88	428	304
Charge-offs	0	0	0	(2)
Allowance for loan losses, Ending balance	44,016	44,365	44,016	44,365
Multifamily Real Estate
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	8,039	6,906	7,734	7,043
Provision for credit losses	765	208	1,070	71
Recoveries	0	0	0	0
Charge-offs	0	0	0	0
Allowance for loan losses, Ending balance	8,804	7,114	8,804	7,114
Construction and Land
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	29,844	26,939	29,171	27,294
Provision for credit losses	(484)	1,071	345	337
Recoveries	29	0	29	384
Charge-offs	0	(25)	(156)	(30)
Allowance for loan losses, Ending balance	29,389	27,985	29,389	27,985
Commercial Business and Small Business Scored
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	33,880	28,673	33,299	26,421
Provision for credit losses	398	2,395	2,060	4,594
Recoveries	403	924	1,046	1,307
Charge-offs	(616)	(138)	(2,340)	(468)
Allowance for loan losses, Ending balance	34,065	31,854	34,065	31,854
Agricultural Business
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	3,573	3,002	3,475	3,190
Provision for credit losses	690	243	677	(77)
Recoveries	19	252	130	384
Charge-offs	(564)	(42)	(564)	(42)
Allowance for loan losses, Ending balance	3,718	3,455	3,718	3,455
One- to Four-Family Residential
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	16,737	9,573	14,729	8,205
Provision for credit losses	1,129	2,796	3,018	4,026
Recoveries	59	25	212	163
Charge-offs	0	0	(34)	0
Allowance for loan losses, Ending balance	17,925	12,394	17,925	12,394
Consumer-other
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	8,971	7,236	8,971	6,951
Provision for credit losses	235	1,730	604	2,096
Recoveries	126	85	412	413
Charge-offs	(289)	(300)	(944)	(709)
Allowance for loan losses, Ending balance	$ 9,043	$ 8,751	9,043	$ 8,751
Commercial Business
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Charge-offs			$ (987)