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Note 1 - Summary of Significant Accounting Policies (Details Textual) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 USD ($) shares | Jan. 01, 2019 USD ($) | Dec. 31, 2018 USD ($) shares
Number Of Limited Partnerships In Housing Investments | 10 |  |
Percentage of Subsidiaries Common Securities Owned by Parent Company | 100.00% |  |
Gross Loans Comprised of Commercial Mortgage Loans Percentage | 48.30% |  |
Residential Mortgages Properties Percentage | 27.10% |  |
Gross Loans Comprised of Commercial Loans Percentage | 18.40% |  |
Federal Home Loan Bank Stock | $ 18,090,000 |  | $ 17,250,000
Minimum Stock Requirement on Outstanding Federal Home Loan Bank Borrowings Shares | shares | 180,900 |  | 150,000
Maximum Loan Size Portfolio Stratification Homogenous Portfolio | $ 500,000 |  |
Variable Interest Entity, Primary Beneficiary, Number of Entities | 9 |  |
Goodwill, Impairment Loss | $ 0 |  |
Number of Reportable Segments | 1 |  |
Operating Lease, Liability, Total | $ 35,873,000 |  | $ 0
Operating Lease, Right-of-Use Asset | $ 33,990,000 |  | $ 0
Accounting Standards Update 2016-02 [Member] |  |  |
Operating Lease, Liability, Total |  | $ 41,200,000 |
Operating Lease, Right-of-Use Asset |  | $ 40,600,000 |
California [Member] |  |  |
Residential Mortgages Properties Percentage | 54.00% |  |

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