Note 7 - Related Party Transactions (Details Textual) - USD ($) $ in Thousands	3 Months Ended																6 Months Ended	12 Months Ended
	Dec. 31, 2024		Sep. 30, 2024	[1]	Jun. 30, 2024	[1]	Mar. 31, 2024	[1]	Dec. 31, 2023		Sep. 30, 2023	[1]	Jun. 30, 2023	[1]	Mar. 31, 2023	[1]	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Investment Income, Net																		$ 2,071	$ 1,566
Gain (Loss) on Investments	$ 1	[1]	$ (2)		$ (1)		$ (3)		$ 0	[1]	$ (4)		$ 43		$ 345			(5)	384
Income Taxes Paid																		76	$ 207
GAMCO Investors, Inc. [Member]
Investment Expense Rate																	0.08%		0.17%
Funds Invested in Mutual Funds	34,242								$ 32,568								$ 34,242	34,242	$ 32,568
Income From Mutual Funds																		1,712	1,677
Investment Income, Net																			1,307
Gain (Loss) on Investments																			370
MtronPTI [Member]
Salaries and Benefits Reimbursed																		105
Excess Separation Costs																		0	28
MtronPTI [Member] | Transitional Administrative and Management Services Agreement [Member]
Monthly Payment	$ 4																$ 4	4
MtronPTI [Member] | Tax Indemnity and Sharing Agreement [Member]
Income Taxes Paid																		$ 0	$ 0

[1] During Q1 and Q2 2023, the net gains primarily relate to the sale of our investments in mutual funds managed by GAMCO Investors, Inc.