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INVESTMENT SECURITIES - Continuous Unrealized Loss on Investment (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | $ (2,346) | $ (486)
Less than 12 months, Fair value | 111,712 | 26,711
Twelve months or more, Gross unrealized losses | (717) | (327)
Twelve months or more, Fair value | 18,848 | 16,790
Total, Gross unrealized losses | (3,063) | (813)
Total, Fair value | 130,560 | 43,501
Residential mortgage-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | (70) | (7)
Less than 12 months, Fair value | 1,115 | 1,196
Twelve months or more, Gross unrealized losses | (228) | (185)
Twelve months or more, Fair value | 1,322 | 1,432
Total, Gross unrealized losses | (298) | (192)
Total, Fair value | 2,437 | 2,628
Commercial mortgage-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | (176) | (8)
Less than 12 months, Fair value | 10,954 | 925
Twelve months or more, Gross unrealized losses | 0 | 0
Twelve months or more, Fair value | 0 | 0
Total, Gross unrealized losses | (176) | (8)
Total, Fair value | 10,954 | 925
Residential collateralized mortgage obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | (701) | (95)
Less than 12 months, Fair value | 21,942 | 7,391
Twelve months or more, Gross unrealized losses | (282) | 0
Twelve months or more, Fair value | 7,159 | 0
Total, Gross unrealized losses | (983) | (95)
Total, Fair value | 29,101 | 7,391
Commercial collateralized mortgage obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | (184) | (39)
Less than 12 months, Fair value | 9,875 | 6,687
Twelve months or more, Gross unrealized losses | (62) | (142)
Twelve months or more, Fair value | 1,956 | 15,358
Total, Gross unrealized losses | (246) | (181)
Total, Fair value | 11,831 | 22,045
Municipal bonds |  |
Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | (1,163) | (337)
Less than 12 months, Fair value | 49,953 | 10,512
Twelve months or more, Gross unrealized losses | (145) | 0
Twelve months or more, Fair value | 8,411 | 0
Total, Gross unrealized losses | (1,308) | (337)
Total, Fair value | 58,364 | $ 10,512
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Less than 12 months, Gross unrealized losses | (52) |
Less than 12 months, Fair value | 17,873 |
Twelve months or more, Gross unrealized losses | 0 |
Twelve months or more, Fair value | 0 |
Total, Gross unrealized losses | (52) |
Total, Fair value | $ 17,873 |

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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456 + Details
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27337-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922890-210455 + Details
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