LOANS RECEIVABLE AND THE ALLOWANCE FOR CREDIT LOSSES (Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	$ 132,099	$ 167,279
(Recapture)/provision for credit losses	(7,376)	(8,035)
Recoveries	994	1,512
Charge-offs	(246)	(4,702)
Allowance for loan losses, Ending balance	125,471	156,054
Commercial Real Estate
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	52,995	57,791
(Recapture)/provision for credit losses	(5,816)	5,359
Recoveries	87	24
Charge-offs	(2)	(3,763)
Allowance for loan losses, Ending balance	47,264	59,411
Multifamily Real Estate
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	7,043	3,893
(Recapture)/provision for credit losses	140	474
Recoveries	0	0
Charge-offs	0	0
Allowance for loan losses, Ending balance	7,183	4,367
Construction and Land
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	27,294	41,295
(Recapture)/provision for credit losses	(994)	(4,955)
Recoveries	384	100
Charge-offs	(5)	0
Allowance for loan losses, Ending balance	26,679	36,440
Commercial Business
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	26,421	35,007
(Recapture)/provision for credit losses	167	(3,786)
Recoveries	149	979
Charge-offs	(82)	(789)
Allowance for loan losses, Ending balance	26,655	31,411
Agricultural Business
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	3,190	4,914
(Recapture)/provision for credit losses	(722)	(297)
Recoveries	118	0
Charge-offs	0	0
Allowance for loan losses, Ending balance	2,586	4,617
One- to Four-Family Residential
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	8,205	9,913
(Recapture)/provision for credit losses	(136)	(2,038)
Recoveries	40	113
Charge-offs	0	0
Allowance for loan losses, Ending balance	8,109	7,988
Consumer
Financing Receivable, Allowance for Loan Losses [Roll Forward]
Allowance for loan losses, Beginning balance	6,951	14,466
(Recapture)/provision for credit losses	(15)	(2,792)
Recoveries	216	296
Charge-offs	(157)	(150)
Allowance for loan losses, Ending balance	$ 6,995	$ 11,820

Amount of increase in allowance for credit loss on financing receivable from recovery.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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