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Securities Held-to-Maturity - Additional Information (Detail) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 USD ($) | Sep. 30, 2019 USD ($) | Dec. 31, 2019 Securities
Investments, Debt and Equity Securities [Abstract] |  |  |
Number of securities determined to be other than temporarily impaired | Securities |  |  | 0
Proceeds from Sale and Maturity of Held-to-maturity Securities | $ | $ 16,441 | $ 2,313 |

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- Definition Amount of cash inflow from the sale or maturity of long-term held-to-maturity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26853-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585 + Details
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