CAPITAL RATIOS AND SHAREHOLDERS' EQUITY - Actual and Required Capital Ratios (Details)	Sep. 30, 2021	Dec. 31, 2020	Jan. 01, 2019
Actual
Total capital to risk-weighted assets, ratio	14.12	13.57
Common equity tier 1 capital to risk-weighted assets, ratio	10.92	10.49
Tier 1 capital to risk-weighted assets, ratio	11.70	11.29
Tier 1 capital to average assets, ratio	8.54	8.12
Capital Required For Capital Adequacy [Abstract]
Regulatory minimum to be well capitalized, Total capital to risk-weighted assets, ratio	10.50	10.50
Regulatory minimum to be well capitalized, Common equity tier 1 capital to risk-weighted assets, ratio	7.00%	7.00%
Regulatory minimum to be well capitalized, Tier 1 capital to risk-weighted assets, ratio	8.50	8.50
Regulatory minimum to be well capitalized, Tier 1 capital to average assets, ratio	5.00	5.00
Bank
Actual
Total capital to risk-weighted assets, ratio	13.92	13.27
Common equity tier 1 capital to risk-weighted assets, ratio	13.02	12.53
Tier 1 capital to risk-weighted assets, ratio	13.02	12.52
Tier 1 capital to average assets, ratio	9.50	9.02
Capital Required For Capital Adequacy [Abstract]
Regulatory minimum to be well capitalized, Total capital to risk-weighted assets, ratio	10.50	10.50
Regulatory minimum to be well capitalized, Common equity tier 1 capital to risk-weighted assets, ratio	7.00%	7.00%	7.00%
Regulatory minimum to be well capitalized, Tier 1 capital to risk-weighted assets, ratio	8.50	8.50	8.5
Regulatory minimum to be well capitalized, Tier 1 capital to average assets, ratio	5.00	5.00	10.5

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The Common equity Tier 1 capital ratio (Common equity Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

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Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework.

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Ratio of Common Equity Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

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Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Ratio of Tier 1 capital to average assets as defined by regulatory framework.

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Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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