Note 7 - Related Party Transactions - Transactions With Related Parties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023
Income	$ 918	$ 888
Expense	(877)	(809)
Assets	43,302		$ 43,145
Liabilities	2,040		$ 1,905
GAMCO Investors, Inc. [Member]
Income	348	408
Expense	0	0
Assets				$ 34,702	$ 34,242
Liabilities				0	0
Mtron Industries Inc [Member]
Income	0	0
Expense	(14)	(14)
Assets				0	0
Liabilities				68	59
Related Party [Member]
Income	348	408
Expense	$ (14)	$ (14)
Assets				34,702	34,242
Liabilities				$ 68	$ 59