Note 1 - Organization (Details Textual) $ / shares in Units, $ in Millions		1 Months Ended			5 Months Ended	6 Months Ended
	Jun. 15, 2024 USD ($) $ / shares shares	Jul. 31, 2025 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) $ / shares shares	Jun. 30, 2024 USD ($) $ / shares shares	Sep. 30, 2025 $ / shares	Mar. 31, 2025 $ / shares	Apr. 18, 2024 $ / shares	Apr. 17, 2024 $ / shares
Common Stock, No Par Value (in dollars per share)							$ 0		$ 0
Common Stock, Par or Stated Value Per Share (in dollars per share)						$ 0.01		$ 0.01
Amplex Holdings [Member]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests | $	$ 3.0	$ 4.5	$ 4.5	$ 3.0
Investment, Shares Acquired During the Period (in shares) | shares	1,674	4,120	2,583	1,674
Investment, Shares Acquired, Price Per Share (in dollars per share)	$ 1,792.55	$ 1,092.26	$ 1,742.16	$ 1,792.55
Subsidiary, Ownership Percentage, Parent	56.50%	66.40%	60.90%	56.50%	56.50%	66.40%
Conversion of Principal and Accrued Interest Into Amplex Shares [Member]
Debt Conversion, Original Debt, Amount | $	$ 0.8				$ 0.8
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares	421				421
Debt Conversion, Converted Instrument, Shares Issued, Price Per Share (in dollars per share)	$ 1,792.55				$ 1,792.55
Broadband [Member] | Amplex Holdings [Member]
Number of Customers						13,400
Fiber [Member] | Amplex Holdings [Member]
Number of Customers						5,400
Fiber Passings [Member] | Amplex Holdings [Member]
Number of Customers						15,000
Amplex Holdings [Member]
Investment, Shares Acquired, Price Per Share (in dollars per share)		$ 1,092.26	$ 1,742.16
Amplex Holdings [Member]
Common Stock, No Par Value (in dollars per share)	$ 0
Business Combination, Voting Equity Interest Acquired, Percentage	51.00%