Note 4 - Fair Value (Details Textual) - USD ($)	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022
Financing Receivable, before Allowance for Credit Loss	$ 735,227,000		$ 711,960,000
Financing Receivable, Allowance for Credit Loss	7,987,000	$ 7,782,000	7,724,000	$ 7,675,000	$ 7,546,000	$ 7,160,000
Other Real Estate	124,000		124,000
Fair Value, Nonrecurring [Member]
Assets, Fair Value Disclosure	0		$ 0
Collateral Pledged [Member]
Financing Receivable, before Allowance for Credit Loss	199
Financing Receivable, Allowance for Credit Loss	$ 12