Note 2 - Investments - Components of EAM's Investment Management Operations (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		9 Months Ended		15 Months Ended
		Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022
Revenues		$ 10,258	$ 10,130			$ 30,397	$ 30,668
Value Line’s non-voting revenues interest		4,120	4,104	$ 12,532	$ 11,113	12,532	11,113
EAM's net income		5,614	7,035	$ 20,015	$ 17,228	20,015	17,228	$ 5,614
EAM Trust [Member]
Other income/(loss)		(70)	119			49	234
Investment management fee waivers and reimbursements		184	88			402	207
12b-1 fee waivers		151	168			493	490
Value Line’s non-voting revenues interest		4,120	4,104			12,532	11,113
EAM's net income	[1]	1,070	1,260			3,640	2,958
EAM Trust [Member] | Investment Advice [Member]
Revenues		7,627	7,827			23,306	21,318
EAM Trust [Member] | Distribution and Shareholder Service [Member]
Revenues		$ 2,362	$ 2,439			$ 7,303	$ 7,194

[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.