Note 7 - Related Party Transactions - Transactions With Related Parties (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Income	$ 1,179	$ 978	$ 3,135	$ 2,683
Expense	(1,041)	(779)	(2,681)	(2,366)
Assets	42,485		42,485		$ 41,850
Liabilities	1,482		1,482		1,168
GAMCO Investors, Inc. [Member]
Income	444	350	1,293	1,172
Expense	0	0	0	0
Assets	33,931		33,931		32,568
Liabilities	0		0		0
Mtron Industries Inc [Member]
Income	0	0	0	0
Expense	(15)	12	(44)	8
Assets	0		0		0
Liabilities	34		34		0
Related Party [Member]
Income	444	350	1,293	1,172
Expense	(15)	$ 12	(44)	$ 8
Assets	33,931		33,931		32,568
Liabilities	$ 34		$ 34		$ 0