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Investment Securities - Unrealized Loss Positions (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Less than 12 continuous months | $ 36,588 |
Greater than or equal to 12 continuous months | 0 |
Total Securities in a loss position | 36,588 |
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Less than 12 continuous months | (164) |
Greater than or equal to 12 continuous months | 0 |
Held-to-maturity, gross unrealized losses | (164) |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 359,280 |
Available-for-sale, greater than 12 continuous months, fair value | 5,119 |
Available-for-sale, total securities in a loss position, fair value | 364,399 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (3,397) |
Available-for-sale, greater than 12 continuous months, unrealized loss | (199) |
Available-for-sale, total securities in a loss position, unrealized loss | (3,596) |
Marketable Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Marketable securities, less than 12 continuous months, fair value | 395,868 | $ 9,918
Marketable securities, greater than 12 continuous months, fair value | 5,119 | 1,790
Marketable securities, total securities in a loss position, fair value | 400,987 | 11,708
Marketable Securities, Continuous Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Marketable securities, less than 12 continuous months, unrealized loss | (3,561) | (25)
Marketable securities, greater than 12 continuous months, unrealized loss | (199) | (55)
Marketable securities, total securities in a loss position, unrealized loss | (3,760) | (80)
MBS pass-through securities issued by FHLMC and FNMA |  |
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Less than 12 continuous months | 17,074 |
Greater than or equal to 12 continuous months | 0 |
Total Securities in a loss position | 17,074 |
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Less than 12 continuous months | (38) |
Greater than or equal to 12 continuous months | 0 |
Held-to-maturity, gross unrealized losses | (38) |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 63,171 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 63,171 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (243) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | (243) |
CMOs issued by FHLMC |  |
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Less than 12 continuous months | 9,320 |
Greater than or equal to 12 continuous months | 0 |
Total Securities in a loss position | 9,320 |
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Less than 12 continuous months | (95) |
Greater than or equal to 12 continuous months | 0 |
Held-to-maturity, gross unrealized losses | (95) |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 142,557 | 5,975
Available-for-sale, greater than 12 continuous months, fair value | 0 | 0
Available-for-sale, total securities in a loss position, fair value | 142,557 | 5,975
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (1,065) | (1)
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 | 0
Available-for-sale, total securities in a loss position, unrealized loss | (1,065) | (1)
CMOs issued by FNMA |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 25,256 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 25,256 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (211) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | (211) |
CMOs issued by GNMA |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 25,879 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 25,879 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (249) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | (249) |
SBA-backed securities |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 8,115 | 0
Available-for-sale, greater than 12 continuous months, fair value | 1,307 | 1,790
Available-for-sale, total securities in a loss position, fair value | 9,422 | 1,790
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (93) | 0
Available-for-sale, greater than 12 continuous months, unrealized loss | (43) | (55)
Available-for-sale, total securities in a loss position, unrealized loss | (136) | (55)
Debentures of government- sponsored agencies |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 50,344 | 3,943
Available-for-sale, greater than 12 continuous months, fair value | 3,812 | 0
Available-for-sale, total securities in a loss position, fair value | 54,156 | 3,943
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (1,021) | (24)
Available-for-sale, greater than 12 continuous months, unrealized loss | (156) | 0
Available-for-sale, total securities in a loss position, unrealized loss | (1,177) | $ (24)
U.S. Treasury securities |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 11,777 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 11,777 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (104) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | (104) |
Obligations of state and political subdivisions |  |
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Less than 12 continuous months | 10,194 |
Greater than or equal to 12 continuous months | 0 |
Total Securities in a loss position | 10,194 |
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Less than 12 continuous months | (31) |
Greater than or equal to 12 continuous months | 0 |
Held-to-maturity, gross unrealized losses | (31) |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 16,494 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 16,494 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (169) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | (169) |
Corporate bonds |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 13,778 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 13,778 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (237) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | (237) |
Asset-backed securities |  |
Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] |  |
Available-for-sale, less than 12 continuous months, fair value | 1,909 |
Available-for-sale, greater than 12 continuous months, fair value | 0 |
Available-for-sale, total securities in a loss position, fair value | 1,909 |
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss [Abstract] |  |
Available-for-sale, less than 12 continuous months, unrealized loss | (5) |
Available-for-sale, greater than 12 continuous months, unrealized loss | 0 |
Available-for-sale, total securities in a loss position, unrealized loss | $ (5) |

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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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