Note 7 - Investment and Equity Securities (Details Textual)		3 Months Ended		9 Months Ended
		Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Equity Securities, FV-NI, Current		$ 972,000		$ 972,000		$ 818,000
Equity Securities, FV-NI, Unrealized Gain (Loss), Total	[1]	(57,000)	$ 102,000	(96,000)	$ 223,000
Equity Securities, FV-NI, Realized Gain (Loss), Total		$ 0	0	$ 0	0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions		174		174
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions		28		28
Available-for-sale Securities, Percentage of Portfolio		81.00%		81.00%
Other-than-temporary Impairment Loss, Debt Securities, Available-for-Sale		$ 0	$ 0	$ 0	$ 0
Asset Pledged as Collateral [Member] | Deposits [Member]
Financial Instruments, Owned, at Fair Value, Total		$ 87,700,000		$ 87,700,000		$ 77,100,000

[1] Not within scope of ASC 606