Note 8 - Shareholders' Equity (Details Textual) - USD ($)	1 Months Ended	3 Months Ended		8 Months Ended	9 Months Ended
	Mar. 31, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2021	Jun. 30, 2022	Feb. 25, 2022	Feb. 24, 2022
Payments for Repurchase of Common Stock		$ 133,000	$ 82,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		0	0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period (in shares)		2,000	0
Share-Based Payment Arrangement, Expense		$ 0	$ 388,000
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount		$ 0	$ 345,000	$ 345,000
Plan1989 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)		229,000	231,000	231,000
Treasury Stock, Common [Member]
Treasury Stock, Shares, Acquired (in shares)		39,965	13,647
Common Class A [Member] | Plan1989 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)		$ 6.05	$ 6.05	$ 6.05
Common Class A [Member] | Plan1997 [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)		2,000	2,000	2,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)		$ 2.74	$ 2.74	$ 2.74
Common Class A [Member] | Treasury Stock, Common [Member]
Treasury Stock, Shares, Acquired (in shares)		39,965	13,647
Payments for Repurchase of Common Stock		$ 133,000	$ 82,000
Share Repurchase Plan Renewal December2012 December2020 [Member]
Stock Repurchase Program, Authorized Amount		$ 5,000,000.0				$ 5,000,000.0	$ 2,750,000
Monthly Dividends Paid [Member]
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share)	$ 0.0075			$ 0.0050	$ 0.0075