LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES - LOANS - Average Recorded Investment (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2021
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	$ 2,384	$ 2,714
Average Recorded Investment, with an allowance recorded	5,299	5,930
Average Recorded Investment	7,683	8,644
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with no related allowance recorded	11	15
Interest Income Recognized, with an allowance recorded	116	131
Interest Income Recognized	127	146
REAL ESTATE LOANS \| Commercial
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded		1,541
REAL ESTATE LOANS \| Construction and development
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	1,233
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with no related allowance recorded	0
REAL ESTATE LOANS \| Home equity.
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	506	579
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with no related allowance recorded	7	9
REAL ESTATE LOANS \| One-to-four-family
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	645	594
Average Recorded Investment, with an allowance recorded	20	40
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with no related allowance recorded	4	6
Interest Income Recognized, with an allowance recorded	0
CONSUMER LOANS \| Indirect home improvement
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with an allowance recorded	671	728
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with an allowance recorded	8	22
CONSUMER LOANS \| Marine
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with an allowance recorded	102	69
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with an allowance recorded	2	3
CONSUMER LOANS \| Other consumer loans
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with an allowance recorded	19	11
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with an allowance recorded	1	1
COMMERCIAL BUSINESS LOANS \| Commercial and industrial
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with an allowance recorded	4,487	5,082
Impaired Financing Receivable, Interest Income [Abstract]
Interest Income Recognized, with an allowance recorded	$ 105	$ 105

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

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Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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