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Concentrations of Credit Risk (Details) - Credit concentration risk - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
U.S. Government, its agencies and Government Sponsored Enterprises (GSEs) | U.S. Government And Government-Sponsored Enterprises |  |
Concentration Risk [Line Items] |  |
Concentration risk amount | $ 1,272.0 | $ 1,535.0
Concentration risk percentage | 86.00% | 87.00%
Non-Government Sponsored Enterprises | U.S. Government And Government-Sponsored Enterprises |  |
Concentration Risk [Line Items] |  |
Concentration risk amount | $ 167.4 | $ 106.1
Non-Government Sponsored Enterprises | Non-Government Sponsored Enterprises |  |
Concentration Risk [Line Items] |  |
Concentration risk percentage | 1.00% | 1.00%
Loans Receivable |  |
Concentration Risk [Line Items] |  |
Concentration risk, threshold for major borrower, percentage | 3.00% | 3.00%
Loans Receivable | Commercial real estate | San Francisco |  |
Concentration Risk [Line Items] |  |
Concentration risk percentage | 3.00% |
Loans on real estate | Residential loans |  |
Concentration Risk [Line Items] |  |
Concentration risk percentage | 90.00% |
Loans on real estate | Commercial real estate | Commercial real estate, non-owner occupied |  |
Concentration Risk [Line Items] |  |
Concentration risk percentage | 6.00% |

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- Definition Concentration Risk, Percentage, Threshold For Major Borrower + References No definition available. + Details
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- Definition Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-21 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 954 -SubTopic 310 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481027/954-310-50-2 + Details
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-42 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-21 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-20 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482861/275-10-50-18 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482861/275-10-50-20 + Details
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