Note 4 - Loan Receivables and Allowance for Loan and Lease Losses (Details Textual)	12 Months Ended
Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	$ 0	$ 176,000
Deteriorated Loans Transferred in, Debt Securities, Accreditable Yield, Period Increase (Decrease), Total	2,000	47,000	$ 92,000
Payments to Acquire Loans Receivable	$ 32,785,000	54,604,000	47,074,000
Maximum Period of Credit Extension of Construction Loans (Month)	1 year 180 days
Loans Receivable, Term to Reset to FHLB Rate (Year)	5 years
Period for Charged Off of Open-End Credits (Day)	180 days
Period for Charged Off of Close-End Credits (Day)	120 days
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	$ 904,000	302,000	$ 503,000
Maximum Period for Charged Off of Consumer Installment Loans (Day)	180 days
Financing Receivable, Troubled Debt Restructuring	$ 15,886,000	$ 10,953,000
Financing Receivable, Modifications, Number of Contracts	6	2	0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts			0
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend	$ 0	$ 0
Financing Receivable, Principal and Interest Deferred Payments	232,400,000
Financing Receivable, Loans Remaining on Deferment	52,600,000
Impaired Financing Receivable, Recorded Investment, Total	24,400,000	19,600,000
Impaired Financing Receivable, Related Allowance	$ 1,400,000	$ 1,500,000
Number of Impaired Loans	26	27
Impaired Financing Receivable, Non-Performing Loans, Discount of Appraisal Value, Selling Costs, Percent	8.00%
Impaired Financing Receivable, Non-Performing Loans, Discount to Appraisal Value, Percent	5.80%	12.00%
Impaired Financing Receivable, Change in Accounting Estimate, Reduction in Loan Charge-offs	$ 266,000
SBA Loans [Member]
Percentage of Principal Balance Guaranteed	75.00%
Syndicated and Leveraged Loans [Member]
Loans and Leases Receivable, Net Amount, Total	$ 55,000,000	$ 71,500,000
Non-Accrual Loans [Member]
Impaired Financing Receivable, Interest Income, Cash Basis Method, Total	156,000	671,000	$ 0
Financing Receivable, Troubled Debt Restructuring	$ 11,508,000	9,337,000
Commercial Real Estate Portfolio Segment [Member]
Maximum Percentage of Credit Extension Based on Market Value of Collateral	75.00%
Financing Receivable, Troubled Debt Restructuring	$ 9,884,000	$ 9,873,000
Financing Receivable, Modifications, Number of Contracts	2	2
Multi-family Real Estate [Member]
Maximum Percentage of Credit Extension Based on Market Value of Collateral	80.00%
Construction Portfolio Segment [Member]
Percentage of Maximum Loan to Value	75.00%
Residential Portfolio Segment [Member]
Payments to Acquire Loans Receivable	$ 17,900,000	$ 47,300,000
Financing Receivable, Troubled Debt Restructuring	928,000	393,000
Consumer Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring	$ 1,074,000	$ 687,000
Financing Receivable, Modifications, Number of Contracts	3
Consumer Portfolio Segment [Member] \| Education Loans [Member]
Payments to Acquire Loans Receivable	$ 14,900,000	$ 7,300,000
Construction to Permanent Portfolio Segment [Member] \| Minimum [Member]
Loans Receivable, Term (Year)	20 years
Construction to Permanent Portfolio Segment [Member] \| Maximum [Member]
Loans Receivable, Term (Year)	25 years
Commercial and Industrial Loans [Member]
Loans and Leases Receivable, Net Amount, Total	$ 21,600,000	9,600,000
Commercial and Industrial Portfolio Segment [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	0	179,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses	$ 0	$ 0

Represents loans remaining on deferment.

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Deferred amounts of principal and interest payments on loans receivable related to loan modification programs offered to financial institution customers affected by COVID-19.

+ References

No definition available.

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Represents the reduction in loan charge-offs for impaired financing receivables during the period attributable to a change in accounting estimate.

+ References

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The percent value of selling costs used to decrease the appraisal value of an impaired loan classified as non-performing.

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The decrease in the appraisal value of an impaired loan when it is classified as non-performing, represented as a percent.

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Period of time between issuance and maturity of loan receivable, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period of time that a loan receivable takes to reset to the FHLB rate, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Maximum percentage of credit extension based on market value of collateral.

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Maximum period for charged off of consumer installment loans.

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Maximum period of credit extension of construction loans.

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The number of impaired loans held.

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Percentage of maximum loan to value.

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Represents percentage of principal balance guaranteed.

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Period for charged off of close end credits.

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Period for charged off of open end credits

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Reserve for loans impairments recorded after acquisition as a result of current information and events which result in it being probable that estimated cash flows will be less than previously expected or because actual cash flows are less than cash flows previously expected. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The increase (decrease) in accreditable yield (the excess of the loan's cash flows expected to be collected over the investor's initial investment in the loan) for the period.

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Number of financing receivables that have been modified by troubled debt restructurings.

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Amount of financing receivable modified as troubled debt restructuring.

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Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

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Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of allowance for credit losses related to recorded investment.

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Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring.

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Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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The cash outflow for the purchase of loan receivable arising from the financing of goods and services.

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