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Investment Securities - Gross unrealized losses (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
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Investment securities available-for-sale |  |
Unrealized losses less than 12 months | $ (12,143) | $ (532)
Fair value less than 12 months | 454,526 | 89,457
Unrealized losses over 12 months | (21) | (13)
Fair value over 12 months | 5,652 | 3,667
Total Unrealized losses | (12,164) | (545)
Total Fair value | 460,178 | 93,124
U. S. Treasury and agencies |  |
Investment securities available-for-sale |  |
Unrealized losses less than 12 months |  | (10)
Fair value less than 12 months |  | 4,509
Unrealized losses over 12 months | (21) | (9)
Fair value over 12 months | 5,650 | 1,309
Total Unrealized losses | (21) | (19)
Total Fair value | 5,650 | 5,818
Obligations of state and political agencies |  |
Investment securities available-for-sale |  |
Unrealized losses less than 12 months | (1,445) |
Fair value less than 12 months | 51,463 |
Total Unrealized losses | (1,445) |
Total Fair value | 51,463 |
Mortgage backed securities - Residential agency |  |
Investment securities available-for-sale |  |
Unrealized losses less than 12 months | (10,268) | (432)
Fair value less than 12 months | 380,454 | 68,494
Unrealized losses over 12 months |  | (4)
Fair value over 12 months |  | 2,356
Total Unrealized losses | (10,268) | (436)
Total Fair value | 380,454 | 70,850
Mortgage backed securities - Commercial |  |
Investment securities available-for-sale |  |
Unrealized losses less than 12 months | (13) |
Fair value less than 12 months | 9,026 |
Total Unrealized losses | (13) |
Total Fair value | 9,026 |
Asset backed securities |  |
Investment securities available-for-sale |  |
Fair value over 12 months | 2 | 2
Total Fair value | 2 | 2
Corporate bonds |  |
Investment securities available-for-sale |  |
Unrealized losses less than 12 months | (417) | (90)
Fair value less than 12 months | 13,583 | 16,454
Total Unrealized losses | (417) | (90)
Total Fair value | $ 13,583 | $ 16,454

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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=121582814&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=121645371&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=121645371&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=121582814&loc=SL82922890-210455 + Details
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