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Note 1 - Significant Accounting Policies (Details Textual) | 3 Months Ended | 4 Months Ended | 6 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2020 USD ($) shares | Mar. 31, 2020 USD ($) | Jun. 30, 2019 shares | Jul. 31, 2020 USD ($) | Jun. 30, 2020 USD ($) shares | Jun. 30, 2019 shares | Apr. 30, 2020 USD ($) | Mar. 23, 2020 | Jan. 01, 2020 USD ($) | Dec. 31, 2019 USD ($) | Jan. 01, 2019 USD ($)
Number of Unconsolidated Business Trusts Formed to Issue Trust Preferred Securities | 5 |  |  |  | 5 |  |  |  |  |  |
Interest Income on Commercial and Mortgage Loans Discontinued Period (Day) |  |  |  |  | 90 days |  |  |  |  |  |
Maximum Delinquency Period for Consumer and Credit Card Loans to be Charged Off (Day) |  |  |  |  | 120 days |  |  |  |  |  |
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Ending Balance | $ 42,800,000 |  |  |  | $ 42,800,000 |  |  |  |  | $ 5,000,000.0 |
Servicing Asset, Total | 846,000,000 |  |  |  | 846,000,000 |  |  |  |  | 727,000,000 |
Goodwill, Impairment Loss |  | $ 0 |  |  | 0 |  |  |  |  |  |
Percentage of Employees Working from Home to Total Employees |  |  |  |  |  |  |  | 75.00% |  |  |
Financing Receivable, Advances under Paycheck Protection Program Liquidity Facility | 0 |  |  |  | 0 |  | $ 43,700,000 |  |  |  |
Loans and Leases Receivable, Allowance, Ending Balance | 32,246,000 |  |  |  | 32,246,000 |  |  |  |  | 23,889,000 |
Retained Earnings (Accumulated Deficit), Ending Balance | 118,239,000 |  |  |  | 118,239,000 |  |  |  |  | $ 107,831,000 |
Accounting Standards Update 2016-02 [Member] |  |  |  |  |  |  |  |  |  |  |
Operating Lease, Right-of-Use Asset |  |  |  |  |  |  |  |  |  |  | $ 1,300,000
Operating Lease, Liability, Total |  |  |  |  |  |  |  |  |  |  | $ 1,300,000
Accounting Standards Update 2016-13 [Member] | Scenario, Plan [Member] |  |  |  |  |  |  |  |  |  |  |
Loans and Leases Receivable, Allowance, Ending Balance |  |  |  |  |  |  |  |  | $ (1,000,000.0) |  |
Retained Earnings (Accumulated Deficit), Ending Balance |  |  |  |  |  |  |  |  | $ 800,000 |  |
SBA, CARES Act, Paycheck Protection Program [Member] |  |  |  |  |  |  |  |  |  |  |
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums, Total | $ 14,700,000 |  |  |  | $ 14,700,000 |  |  |  |  |  |
Core Deposits [Member] |  |  |  |  |  |  |  |  |  |  |
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year) |  |  |  |  | 10 years |  |  |  |  |  |
Subsequent Event [Member] | SBA, CARES Act, Paycheck Protection Program [Member] |  |  |  |  |  |  |  |  |  |  |
Number of Loans Originated Under the Paycheck Protection Program |  |  |  | 2,200 |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  |  |  | $ 550,000,000 |  |  |  |  |  |  |
Commercial Portfolio Segment [Member] |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Payment Deferrals, Interest-only Amendments, Period (Day) | 90 days |  |  |  |  |  |  |  |  |  |
Financing Receivable, Payment Deferrals, Principal and Interest, Period (Day) | 90 days |  |  |  |  |  |  |  |  |  |
Financing Receivable, Payment Deferrals, Interest Rate | 0.00% |  |  |  | 0.00% |  |  |  |  |  |
Financing Receivable, Number of Interest Only Payment Deferrals | 463 |  |  |  | 463 |  |  |  |  |  |
Financing Receivable With Interest Only Deferred Payments | $ 421,000,000 |  |  |  | $ 421,000,000 |  |  |  |  |  |
Financing Receivable, Number of Principal and Interest Payment Deferrals | 242 |  |  |  | 242 |  |  |  |  |  |
Financing Receivable With Principal and Interest Deferred Payments | $ 298,000,000 |  |  |  | $ 298,000,000 |  |  |  |  |  |
Financing Receivable, Originated, Single Payment | $ 8,100,000 |  |  |  | $ 8,100,000 |  |  |  |  |  |
Commercial Portfolio Segment [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Number of Principal and Interest Payment Deferrals |  |  |  | 21 |  |  |  |  |  |  |
Financing Receivable With Principal and Interest Deferred Payments |  |  |  | $ 117,000,000 |  |  |  |  |  |  |
Financing Receivable, Number of Interest Payment Deferrals |  |  |  | 16 |  |  |  |  |  |  |
Financing Receivable With Interest Deferred Payments |  |  |  | $ 31,000,000.0 |  |  |  |  |  |  |
Financing Receivable With Principal and Interest Deferred Payments, Single Payment Loans |  |  |  | 4,200,000 |  |  |  |  |  |  |
Retail Portfolio Segment [Member] |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Payment Deferrals, Principal and Interest, Period (Day) | 90 days |  |  |  |  |  |  |  |  |  |
Financing Receivable, Number of Principal and Interest Payment Deferrals | 260 |  |  |  | 260 |  |  |  |  |  |
Financing Receivable With Principal and Interest Deferred Payments | $ 23,800,000 |  |  |  | $ 23,800,000 |  |  |  |  |  |
Retail Portfolio Segment [Member] | Subsequent Event [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |
Financing Receivable, Additional Principal and Interest Payment Deferments |  |  |  | $ 2,000,000.0 |  |  |  |  |  |  |
Restricted Stock [Member] |  |  |  |  |  |  |  |  |  |  |
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights (in shares) | shares | 256,000 |  | 261,000 |  | 256,000 | 261,000 |  |  |  |  |
Share-based Payment Arrangement, Option [Member] |  |  |  |  |  |  |  |  |  |  |
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights (in shares) | shares | 2,000 |  | 10,000 |  | 2,000 | 10,000 |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares | 9,000 |  | 7,000 |  | 9,000 | 7,000 |  |  |  |  |

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