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Note 3 - Loans and Allowance for Credit Losses (Details Textual) - USD ($) | 3 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2022 | Mar. 31, 2021 | Jan. 01, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Aug. 08, 2020
Financing Receivable, before Allowance for Credit Loss, Total |  | $ 3,555,790,000 |  |  | $ 3,453,459,000 |  |
Increase (Decrease) in Finance Receivables |  | $ 102,000,000 |  |  |  |  |
Loans and Leases Receivable, Percentage Period Increase (Decrease) |  | 3.00% |  |  |  |  |
Financing Receivable, Nonaccrual, Interest Income |  | $ 0 | $ 0 |  |  |  |
Financing Receivable, Nonaccrual |  | 1,612,000 |  |  |  |  |
Financing Receivable, Accruing Trouble Debt Restructurings, Interest Income |  |  | 400,000 |  |  |  |
Maximum [Member] |  |  |  |  |  |  |
Interest Lost on Nonaccrual Loans |  | 100,000 | 100,000 |  |  |  |
SBA, CARES Act, Paycheck Protection Program [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  |  |  |  |  |  | $ 553,000,000
Financing Receivable With No Allowance [Member] |  |  |  |  |  |  |
Financing Receivable, Nonaccrual |  | 1,500,000 |  |  |  |  |
Commercial Portfolio Segment [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  | 3,004,562,000 |  |  | 2,950,424,000 |  |
Financing Receivable, Nonaccrual |  | 0 |  |  |  |  |
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total | [1] | 1,153,814,000 |  |  | 1,137,419,000 |  |
Financing Receivable, Troubled Debt Restructuring |  | 2,829,000 | 3,760,000 |  | 4,973,000 | $ 6,414,000 |
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Grades 1-4 [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total | [2] | 719,267,000 |  |  | 729,224,000 |  |
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | SBA, CARES Act, Paycheck Protection Program [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  | 12,200,000 |  |  | 40,100,000 |  |
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | SBA, CARES Act, Paycheck Protection Program [Member] | Grades 1-4 [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  | 12,200,000 |  |  | 40,100,000 |  |
Retail Portfolio Segment [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  | 551,228,000 |  |  | 503,035,000 |  |
Financing Receivable, Nonaccrual |  | 1,612,000 |  |  |  |  |
Retail Portfolio Segment [Member] | Home Equity Loan [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  | 31,900,000 |  |  | 29,500,000 |  |
Retail Portfolio Segment [Member] | Other Consumer Loans [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total | [3] | 28,672,000 |  |  | 60,488,000 |  |
Financing Receivable, Troubled Debt Restructuring |  | 13,000 | 1,099,000 |  | 1,202,000 | 1,146,000 |
Retail Portfolio Segment [Member] | Other Consumer Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring |  |  |  | $ (1,200,000) |  |  |
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] |  |  |  |  |  |  |
Financing Receivable, before Allowance for Credit Loss, Total |  | 522,556,000 |  |  | 442,547,000 |  |
Financing Receivable, Troubled Debt Restructuring |  | $ 2,346,000 | $ 820,000 |  | $ 627,000 | $ 806,000 |
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] |  |  |  |  |  |  |
Financing Receivable, Troubled Debt Restructuring |  |  |  | $ 1,200,000 |  |  |
[1] | For March 31, 2022, and December 31, 2021, includes $12.2 million and $40.1 million in loans originated under the Paycheck Protection Program, respectively.
[2] | Included in Commercial and Industrial Loans Grades 1 – 4 are $12.2 million of loans originated under the Paycheck Protection Program.
[3] | In conjunction with the adoption of the CECL methodology effective January 1, 2022, home equity lines of credit were reclassified to 1-4 family mortgage loans from other consumer loans. Home equity lines of credit totaled $31.9 million and $29.5 million as of March 31, 2022 and December 31, 2021, respectively.

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