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Investment Securities - Pledged and Transferred Securities (Details) - USD ($) $ in Thousands | Jun. 30, 2023 | Dec. 31, 2022
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Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | $ 868,041 | $ 238,570
State of California |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | 200,564 | 236,833
Public deposits |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | 199,327 | 235,587
Trust deposits |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | 672 | 677
Internal checking account |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | 565 | 569
Bankruptcy trustee deposits |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | 1,594 | 1,737
FHLB Securities Backed Credit Program |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | 391,668 | 0
Federal Reserve Bank Term Funding Program |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |
Available-for-sale securities pledged as collateral | $ 274,215 | $ 0

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- Definition Fair value of the securities pledged as collateral against securities loaned. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483444/210-20-55-12 + Details
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