Note 11 - Borrowing Arrangements (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Advances from Federal Home Loan Banks, Total	$ 190,000,000	$ 190,000,000	$ 0
Long-term Line of Credit, Total	0	0	0
Federal Home Loan Bank Advances [Member]
Advances from Federal Home Loan Banks, Total			0
Federal Reserve Bank Of San Francisco Secured Line Of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	14,900,000	14,900,000
Loans Pledged as Collateral	28,600,000	28,600,000
Federal Home Loan Bank Of San Francisco Secured Line Of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	859,900,000	859,900,000
Loans Pledged as Collateral	1,100,000,000	1,100,000,000
Federal Home Loan Bank Overnight Advances [Member]
Advances from Federal Home Loan Banks, Total			$ 0
Interest Expense, Loans from Other Federal Home Loan Banks	444,000	1.0
Zions Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	20,000,000.0	20,000,000.0
Wells Fargo Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	10,000,000.0	10,000,000.0
Wells Fargo Bank [Member] \| Line of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	2,000,000.0	2,000,000.0
First Horizon National Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	12,000,000.0	12,000,000.0
Pacific Coast Bankers' Bank [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 50,000,000.0	$ 50,000,000.0

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Amount of interest expense on loans received from another Federal Home Loan Bank (FHLB).

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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