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LOANS RECEIVABLE - Impaired Loans (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 4,155,000	$ 4,464,000
Unpaid Principal Balance	4,508,000	4,844,000
Related Allowance	556,000	599,000
Average Recorded Investment	4,207,000	4,529,000
Interest Income Recognized	67,000	133,000
Interest Income Collected	66,000	121,000
Adjustable-rate loans	101,900,000	109,600,000
Fixed rate loans	38,700,000	42,200,000
Interest only loans	1,900,000	2,000,000.0
Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,152,000	4,460,000
Unpaid Principal Balance	4,502,000	4,837,000
Related Allowance	556,000	599,000
Average Recorded Investment	4,203,000	4,524,000
Interest Income Recognized	67,000	133,000
Interest Income Collected	66,000	121,000
One- to four-family residential
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,920,000	3,209,000
Unpaid Principal Balance	3,270,000	3,586,000
Related Allowance	556,000	599,000
Average Recorded Investment	2,962,000	3,266,000
Interest Income Recognized	39,000	86,000
Interest Income Collected	38,000	78,000
Construction & land
Financing Receivable, Impaired [Line Items]
Recorded Investment	46,000	46,000
Unpaid Principal Balance	46,000	46,000
Average Recorded Investment	46,000	48,000
Multi-family residential
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,186,000	1,205,000
Unpaid Principal Balance	1,186,000	1,205,000
Average Recorded Investment	1,195,000	1,210,000
Interest Income Recognized	28,000	47,000
Interest Income Collected	28,000	43,000
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment	3,000	4,000
Unpaid Principal Balance	6,000	7,000
Average Recorded Investment	$ 4,000	$ 5,000

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- Definition

Amount of interest income collected on financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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