Note 4 - Investments - Summarized Financial Information (Details) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended
		Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Total revenue		$ 4,120			$ 3,068			$ 10,902	$ 8,891
Total expense		3,327			3,252			9,819	9,482
Provision for income tax		6			(49)			1	68
Net income (loss)		1,289	$ 948	$ (276)	157	$ (218)	$ (7)	1,962	(67)
Loss recorded in the Consolidated Statements of Operations								217	273
Amortized cost		0						0		$ 1,000
Fair value total		2,010						2,010		3,183
Amortized cost total		$ 2,010						$ 2,010		$ 3,183
HC Government Realty Trust, Inc [Member]
Equity Method Investment, Ownership Percentage		28.00%						28.00%		28.00%
Investment in affiliate, balance		$ 9,224						$ 9,224		$ 9,265
Loss recorded in the Consolidated Statements of Operations	[1]	$ 0			(2)			$ (41)	(273)
HC Government Realty Trust, Inc [Member] | Series B Cumulative Convertible Preferred Stock [Member]
Equity Method Investment, Ownership Percentage	[2]	27.90%						27.90%		27.90%
Investment in affiliate, balance	[2]	$ 9,215						$ 9,215		$ 9,256
Loss recorded in the Consolidated Statements of Operations	[1],[2]	$ 0			0			$ (41)	0
HC Government Realty Trust, Inc [Member] | Common Stock of Investee [Member]
Equity Method Investment, Ownership Percentage		0.10%						0.10%		0.10%
Investment in affiliate, balance		$ 9						$ 9		$ 9
Loss recorded in the Consolidated Statements of Operations	[1]	0			(2)			0	(273)
US Government Agencies Debt Securities [Member]
Fair value	[3]	0						0		1,000
Amortized cost	[3]	0						0		1,000
Investment in Limited Partnership [Member]
Fair value	[4]	2,010						2,010		2,183
Investments in limited partnerships	[4]	2,010						2,010		$ 2,183
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] | ACMAT Corporation [Member]
Total revenue		1,044			1,268			2,719	2,809
Total expense		774			824			2,416	2,365
Pre-tax earnings		270			444			303	444
Provision for income tax		(36)			(36)			(36)	4
Net income (loss)		306			480			339	440
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] | HC Realty [Member]
Total revenue		5,333			5,365			15,943	15,977
Total expense		8,837			10,490			25,504	28,139
Net income (loss)		$ (3,504)			$ (5,125)			$ (9,561)	$ (12,162)

[1] Loss from these investments is included in “Income (loss) from investments in related parties, net” in the Unaudited Consolidated Statements of Operations. Since HC Realty is a REIT and not a taxable entity, the loss is not reported net of taxes.

[2] Represents investments in shares of HC Series B Stock with a basis of $10.25 million. Each share of HC Series B Stock has voting rights on an as converted basis and can be converted into shares of HC Common Stock at a conversion ratio equal to $10.00 per share divided by the lesser of $9.10 per share or the fair market value per share of HC Common Stock, subject to adjustment upon the occurrence of certain events.

[3] The Company's portfolio of fixed-income securities fully matured in the first quarter of 2025. There were no unrealized gains or losses on fixed-income securities as of December 31, 2024.

[4] As of June 30, 2025, there are no unfunded commitments related to the investment in limited partnership. This limited partnership invests in property catastrophe risk through customized reinsurance solutions. The underlying assets of the limited partnership are one year or less in duration and the Company’s proceeds may be redeemed or reinvested annually. Changes in net asset value of the investment in limited partnership are included in "Net investment income" on the Company’s Unaudited Consolidated Statements of Operations.