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Investment Securities - Securities Sold and Pledged as Collateral (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Available-for-sale: |  |  |
Sales proceeds | $ 6,632 | $ 33,756 | $ 66,081
Gross realized gains | 1 | 916 | 214
Gross realized losses | (17) | (1) | $ (159)
Available-for-sale securities pledged as collateral | 217,849 | 132,431 |
Public Deposits |  |  |
Available-for-sale: |  |  |
Available-for-sale securities pledged as collateral | 213,861 | 131,051 |
Trust Deposits |  |  |
Available-for-sale: |  |  |
Available-for-sale securities pledged as collateral | 729 | 751 |
Internal checking account |  |  |
Available-for-sale: |  |  |
Available-for-sale securities pledged as collateral | 614 | 629 |
State of California |  |  |
Available-for-sale: |  |  |
Available-for-sale securities pledged as collateral | 215,204 | 132,431 |
Bankruptcy Trustee Deposits Pledged With Federal Reserve Bank |  |  |
Available-for-sale: |  |  |
Available-for-sale securities pledged as collateral | $ 2,645 | $ 0 |

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- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563 + Details
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- Definition Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 50 -Paragraph 1A -Subparagraph (b)(1)(i) -URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729 + Details
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