Note 3 - Fair Value Measurements - Carrying Values and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt securities available for sale (at fair value)	$ 490,271	$ 502,762	[1]
Tax-exempt state and political subdivisions	93,737	94,227	[1]
Equity investments (at fair value)	11,571	10,958	[1]
Cash surrender value of life insurance policies and annuities	86,230	85,679	[1]
Derivative financial instruments	36,803	33,145	[1]
Reported Value Measurement [Member]
Cash and cash equivalents	55,656	52,232
Debt securities available for sale (at fair value)	490,271	502,762
Tax-exempt state and political subdivisions	93,737	94,227
Equity investments (at fair value)	11,571	10,958
Other investments	21,842	21,130
Loans, net	3,647,810	3,633,522
Accrued interest receivable	20,238	20,004
Cash surrender value of life insurance policies and annuities	86,230	85,679
Derivative financial instruments	36,803	33,145
Assets, Fair Value Disclosure	4,464,158	4,453,659
Deposits	3,748,415	3,715,148
Short-term borrowings	262,359	302,957
Long-term borrowings	630	637
Subordinated debentures	103,904	103,782
Subordinated debentures owed to unconsolidated subsidiary trusts	19,589	19,589
Accrued interest payable	4,646	3,980
Financial Liabilities Fair Value Disclosure	4,139,543	4,146,093
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	55,656	52,232
Debt securities available for sale (at fair value)	490,271	502,762
Tax-exempt state and political subdivisions	87,029	88,319
Equity investments (at fair value)	11,571	10,958
Other investments	21,842	21,130
Loans, net	3,483,889	3,467,324
Accrued interest receivable	20,238	20,004
Cash surrender value of life insurance policies and annuities	86,230	85,679
Derivative financial instruments	36,803	33,145
Assets, Fair Value Disclosure	4,293,529	4,281,553
Deposits	3,740,170	3,706,250
Short-term borrowings	262,359	302,957
Long-term borrowings	632	642
Subordinated debentures	91,605	90,902
Subordinated debentures owed to unconsolidated subsidiary trusts	19,589	19,589
Accrued interest payable	4,646	3,980
Financial Liabilities Fair Value Disclosure	4,119,001	4,124,320
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	23,706	21,834
Debt securities available for sale (at fair value)	0	0
Tax-exempt state and political subdivisions	0	0
Equity investments (at fair value)	7,107	6,557
Other investments	0	0
Loans, net	0	0
Accrued interest receivable	0	0
Cash surrender value of life insurance policies and annuities	0	0
Derivative financial instruments	0	0
Assets, Fair Value Disclosure	30,813	28,391
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Subordinated debentures	0	0
Subordinated debentures owed to unconsolidated subsidiary trusts	0	0
Accrued interest payable	0	0
Financial Liabilities Fair Value Disclosure	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	31,950	30,398
Debt securities available for sale (at fair value)	485,804	498,155
Tax-exempt state and political subdivisions	87,029	88,319
Equity investments (at fair value)	4,464	4,401
Other investments	21,842	21,130
Loans, net	20,552	14,373
Accrued interest receivable	20,238	20,004
Cash surrender value of life insurance policies and annuities	86,230	85,679
Derivative financial instruments	36,803	33,145
Assets, Fair Value Disclosure	794,912	795,604
Deposits	3,740,170	3,706,250
Short-term borrowings	262,359	302,957
Long-term borrowings	632	642
Subordinated debentures	91,605	90,902
Subordinated debentures owed to unconsolidated subsidiary trusts	19,589	19,589
Accrued interest payable	4,646	3,980
Financial Liabilities Fair Value Disclosure	4,119,001	4,124,320
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Debt securities available for sale (at fair value)	4,467	4,607
Tax-exempt state and political subdivisions	0	0
Equity investments (at fair value)	0	0
Other investments	0	0
Loans, net	3,463,337	3,452,951
Accrued interest receivable	0	0
Cash surrender value of life insurance policies and annuities	0	0
Derivative financial instruments	0	0
Assets, Fair Value Disclosure	3,467,804	3,457,558
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Subordinated debentures	0	0
Subordinated debentures owed to unconsolidated subsidiary trusts	0	0
Accrued interest payable	0	0
Financial Liabilities Fair Value Disclosure	$ 0	$ 0

[1] Derived from audited consolidated financial statements.