Note 19 - Tax Credit Investments (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Investment, Proportional Amortization Method, Elected, Amount	$ 45,996,000		$ 45,996,000		$ 29,256,000
Affordable Housing Tax Credits [Member]
Investment, Proportional Amortization Method, Elected, Amount	33,700,000		33,700,000		26,500,000
Investment Program, Proportional Amortization Method, Elected, Commitment	16,800,000		16,800,000		13,200,000
Investment Program, Proportional Amortization Method, Applied, Amortization Expense	810,000	$ 539,000	2,000,000	$ 1,500,000
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization Expense	$ 976,000	$ 666,000	2,400,000	1,800,000
Investment Program, Proportional Amortization Method, Elected, Impairment Loss			$ 0	$ 0
Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Income or Comprehensive Income [Extensible Enumeration]	Income Tax Expense (Benefit)	Income Tax Expense (Benefit)	Income Tax Expense (Benefit)	Income Tax Expense (Benefit)
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Cash Flows [Extensible Enumeration]	Increase (Decrease) in Other Operating Assets and Liabilities, Net	Increase (Decrease) in Other Operating Assets and Liabilities, Net	Increase (Decrease) in Other Operating Assets and Liabilities, Net	Increase (Decrease) in Other Operating Assets and Liabilities, Net
Solar Investment Tax Credit [Member]
Investment, Proportional Amortization Method, Elected, Amount	$ 12,300,000		$ 12,300,000		3,300,000
Investment Program, Proportional Amortization Method, Elected, Commitment	13,300,000		13,300,000		$ 1,700,000
Investment Program, Proportional Amortization Method, Applied, Amortization Expense	5,000,000	$ 2,400,000	6,100,000	$ 4,800,000
Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization Expense	$ 5,500,000	$ 2,600,000	$ 7,000,000	$ 2,600,000

Amount of impairment loss for investment that generates income tax credit and other income tax benefit under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under tax credit program not meeting condition for accounting under proportional amortization method.

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