LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 132,099	$ 167,279	$ 100,559
Provision for Loan and Lease Losses	(8,158)	(33,112)	(64,285)
Recoveries	3,921	4,615	6,263
Charge-offs	(2,713)	(6,683)	(11,640)
Ending balance	$ 141,465	$ 132,099	$ 167,279
Net loan charge-offs as a percent of average outstanding loans during the period	0.01%	(0.02%)	(0.05%)
Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ (7,812)
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 52,995	$ 57,791	30,591
Provision for Loan and Lease Losses	(9,299)	(2,758)	(31,643)
Recoveries	392	1,729	275
Charge-offs	(2)	(3,767)	(1,854)
Ending balance	$ 44,086	$ 52,995	$ 57,791
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	(0.02%)	(0.02%)
Commercial Real Estate [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ 2,864
Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 7,043	$ 3,893	4,754
Provision for Loan and Lease Losses	(691)	(3,209)	(1,409)
Recoveries	0	0	0
Charge-offs	0	(59)	(66)
Ending balance	$ 7,734	$ 7,043	$ 3,893
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	0.00%	0.00%
Multifamily Real Estate [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ 2,204
Construction and Land [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 27,294	$ 41,295	22,994
Provision for Loan and Lease Losses	(1,523)	(14,101)	(15,781)
Recoveries	384	100	105
Charge-offs	(30)	0	(100)
Ending balance	$ 29,171	$ 27,294	$ 41,295
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	0.00%	0.00%
Construction and Land [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ (2,515)
Commercial business [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 26,421	$ 35,007	23,370
Provision for Loan and Lease Losses	(6,654)	(8,621)	(12,615)
Recoveries	1,923	1,797	3,265
Charge-offs	(1,699)	(1,762)	(7,253)
Ending balance	$ 33,299	$ 26,421	$ 35,007
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	0.00%	(0.04%)
Commercial business [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ (3,010)
Agricultural Business [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 3,190	$ 4,914	4,120
Provision for Loan and Lease Losses	(148)	(1,573)	(87)
Recoveries	475	30	1,823
Charge-offs	(42)	(181)	(591)
Ending balance	$ 3,475	$ 3,190	$ 4,914
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	0.00%	0.01%
Agricultural Business [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ 351
One- to four-family residential [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 8,205	$ 9,913	4,136
Provision for Loan and Lease Losses	(6,343)	(1,907)	(1,679)
Recoveries	181	199	467
Charge-offs	0	0	(136)
Ending balance	$ 14,729	$ 8,205	$ 9,913
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	0.00%	0.00%
One- to four-family residential [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ (7,125)
Consumer [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 6,951	$ 14,466	8,202
Provision for Loan and Lease Losses	(2,394)	(7,361)	(4,603)
Recoveries	566	760	328
Charge-offs	(940)	(914)	(1,640)
Ending balance	$ 8,971	$ 6,951	$ 14,466
Net loan charge-offs as a percent of average outstanding loans during the period	0.00%	0.00%	(0.01%)
Consumer [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ (2,973)
Unallocated [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 0	$ 0	2,392
Provision for Loan and Lease Losses	0	0	0
Recoveries	0	0	0
Charge-offs	0	0	0
Ending balance	$ 0	$ 0	0
Unallocated [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provision for Loan and Lease Losses			$ 2,392

Net loan charge-offs as a percent of average outstanding loans during the period

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- Definition

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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- Definition

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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