Note 3 - Investments (Details Textual)		3 Months Ended		12 Months Ended
	Jun. 30, 2025 $ / shares shares	Mar. 31, 2026 USD ($) shares	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2025 USD ($)	Sep. 30, 2025 USD ($) shares	Sep. 30, 2024 USD ($) $ / shares
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		$ 18,926,000			$ 18,841,000
Equity in Earnings of Related Parties Equity Method Investees		(86,000)	$ 0
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments						$ 0
Fair Value, Nonrecurring [Member]
Assets, Fair Value Disclosure		0
Related Party [Member]
Investments					1,100,000
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval		536,000
Equity Securities, FV-NI, Gain (Loss)		155,000	245,000
Related Party [Member] | Accounts Receivable [Member]
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval		$ 14,000			526,000
Related Party [Member] | Accounts Payable [Member]
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval					355,000
Fixed Income Securities [Member]
Debt Securities, Unrealized Gain (Loss)				$ 0
HC Government Realty Trust, Inc [Member]
Ownership Percentage		28.00%				28.00%
HC Government Realty Trust, Inc [Member] | Series B Cumulative Convertible Preferred Stock [Member]
Equity Method Investment, Aggregate Cost							$ 10,250,000
Preferred Stock, Convertible, Conversion Price (in dollars per share) | $ / shares							$ 10
Convertible Preferred Stock, Maximum Conversion Price (in dollars per share) | $ / shares							$ 9.1
HC Government Realty Trust, Inc [Member] | Common Stock of Investee [Member]
Equity Method Investment, Other-than-Temporary Impairment		$ 0	$ 41,000
Investments		$ 1,100,000
HC Government Realty Trust, Inc [Member] | Common Stock of Investee [Member]
Investment Owned, Balance, Shares (in shares) | shares		250				250
HC Government Realty Trust, Inc [Member] | Series B Cumulative Convertible Preferred Stock [Member]
Investment Owned, Balance, Shares (in shares) | shares		1,025,000				1,025,000
ACMAT Corporation [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		$ 12,700,000			$ 12,600,000
Equity in Earnings of Related Parties Equity Method Investees		$ 86,000
Assignment and Contribution Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares	2,899,876
Assignment and Contribution Agreement [Member] | ACMAT Common Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares	10,203
Common Stock, No Par Value (in dollars per share) | $ / shares	$ 0
Votes Per Share	1
Assignment and Contribution Agreement [Member] | ACMAT Class A Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares) | shares	291,656
Common Stock, No Par Value (in dollars per share) | $ / shares	$ 0
Votes Per Share	10
Assignment and Contribution Agreement [Member] | ACMAT Corporation [Member]
Subsidiary, Ownership Percentage, Parent	39.10%
Investment, Voting Power	10.40%