Note 5 - Premises, Equipment, Other Assets and Other Liabilities (Details Textual) $ / shares in Units, shares in Thousands, $ in Thousands			12 Months Ended
	Sep. 28, 2023	Jun. 29, 2023	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 29, 2023 $ / shares
Depreciation, Depletion and Amortization, Nonproduction			$ 2,942	$ 2,899	$ 2,978
Share Price (in dollars per share) | $ / shares			$ 56.41
LIHTC Investments			$ 28,667	34,421
Qualified Affordable Housing Project Investments, Commitment			$ 15,561	22,647
Lessee, Operating Lease, Term of Contract (Year)			5 years
Lessee, Operating Lease, Renewal Term (Year)			5 years
Operating Lease, Liability			$ 18,814	15,746
Operating Lease, Weighted Average Remaining Lease Term (Year)			3 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent			2.94%
Operating Lease, Right-of-Use Asset			$ 18,814	15,746
Occupancy and Equipment Expense [Member]
Operating Lease, Cost			6,604	$ 6,575	$ 6,581
Contingent Commitment, Year 1 [Member]
Qualified Affordable Housing Project Investments, Commitment			14,077
Contingent Commitment, Year 2 [Member]
Qualified Affordable Housing Project Investments, Commitment			600
Contingent Commitment, Year 3 [Member]
Qualified Affordable Housing Project Investments, Commitment			145
Contingent Commitment, Year 4 [Member]
Qualified Affordable Housing Project Investments, Commitment			189
Contingent Commitment, Thereafter [Member]
Qualified Affordable Housing Project Investments, Commitment			$ 550
Visa Inc. [Member]
Investment Owned, Balance, Shares (in shares) | shares			211
Conversion Rate of Class B Common Stock into Class A Common Stock	1.5875	1.5902
Share Price (in dollars per share) | $ / shares						$ 260.35
Visa Inc. [Member] | Reported Value Measurement [Member]
Investment Owned, at Fair Value			$ 0