Note 2 - Investments - Components of EAM's Investment Management Operations (Details) - USD ($) $ in Thousands		3 Months Ended						9 Months Ended
		Jan. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	Jan. 31, 2023	Oct. 31, 2022	Jul. 31, 2022	Jan. 31, 2024	Jan. 31, 2023
Revenues		$ 9,131			$ 9,967			$ 28,484	$ 29,977
Value Line’s non-voting revenues interest		3,083			2,512			8,420	7,917
EAM's net income		5,885	$ 3,488	$ 4,859	5,248	$ 4,330	$ 4,458	14,232	14,036
EAM Trust [Member]
Other income		192			146			295	150
Investment management fee waivers and reimbursements		77			73			239	104
12b-1 fee waivers		24			26			72	80
Value Line’s non-voting revenues interest		3,083			2,512			8,420	7,917
EAM's net income	[1]	812			346			1,842	1,198
EAM Trust [Member] | Investment Advice [Member]
Revenues		6,320			4,809			17,388	14,951
EAM Trust [Member] | Distribution and Shareholder Service [Member]
Revenues		$ 1,632			$ 1,457			$ 4,811	$ 4,507

[1] Represents EAM's net income, after giving effect to Value Line’s non-voting revenues interest, but before distributions to voting profits interest holders and to the Company in respect of its 50% non-voting profits interest.