Note 3 - Investments - Components of Investments (Details) - USD ($)		Sep. 30, 2023		Jun. 30, 2023
Cost		$ 18,751,000		$ 19,601,000
Unrealized gains losses		(6,831,000)		(6,396,000)
Investments in equity securities		11,920,000		13,205,000
Investments in available-for-sale debt securities, amortized cost		7,414,000	[1]	7,729,000
Unrealized gains		1,436,000		1,707,000
Unrealized losses		0		0
Unrealized gains (losses)		(2,507,000)		(2,428,000)
Investments in debt securities		6,343,000	[1]	7,008,000
Allowance for credit loss		0		0
Amortized cost, held-to-maturity	[2]	795,000		1,000,000
Unrecognized gains, held-to-maturity	[2]	0		0
Unrecognized losses, held-to-maturity	[2]	(205,000)		(232,000)
Fair value, held-to-maturity	[2]	795,000		768,000
Allowance for credit loss, held-to-maturity	[2]	205,000		0
Equity Securities International [Member]
Cost		6,680,000		6,679,000
Unrealized gains losses		(6,255,000)		(5,901,000)
Investments in equity securities		425,000		778,000
Equity Securities Domestic [Member]
Cost		45,000		45,000
Unrealized gains losses		(45,000)		(45,000)
Investments in equity securities		0		0
Mutual Funds Fixed Income [Member]
Cost		11,097,000		11,947,000
Unrealized gains losses		(304,000)		(305,000)
Investments in equity securities		10,793,000		11,642,000
Mutual Funds Global Equity [Member]
Cost		929,000		930,000
Unrealized gains losses		(227,000)		(145,000)
Investments in equity securities		$ 702,000		$ 785,000

[1] Principal payments of $750,000 are due quarterly with a final maturity date in January 2026.

[2] Held-to-maturity debt investments are carried at amortized cost, and the fair value is classified as Level 2 according to the fair value hierarchy.