Condensed Statements of Stockholders' Equity (Unaudited) - USD ($)	Preferred Stock [Member]	Common Stock Class A [Member]	Additional Paid-in Capital [Member]	Treasury Stock (Common Class A) [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Beginning balance, value at Apr. 30, 2022	$ 99,000	$ 850,000	$ 1,934,000	$ (4,547,000)	$ (137,000)	$ 50,843,000	$ 49,042,000
Beginning balance, shares at Apr. 30, 2022	4,100	8,502,881		3,571,693
Purchases of common stock				$ (3,000)			(3,000)
Purchases of common stock, shares				270
Dividend declared at $0.65 per common share outstanding						(2,959,000)	(2,959,000)
Unrealized (loss), net of tax effect					(126,000)		(126,000)
Net Income						1,659,000	1,659,000
Prior period adjustment for provisions related to depreciation						(161,000)	(161,000)
Ending balance, value at Oct. 31, 2022	$ 99,000	$ 850,000	1,934,000	$ (4,550,000)	(263,000)	49,382,000	47,452,000
Ending balance, shares at Oct. 31, 2022	4,100	8,502,881		3,571,963
Beginning balance, value at Jul. 31, 2022	$ 99,000	$ 850,000	1,934,000	$ (4,549,000)	(117,000)	51,733,000	49,950,000
Beginning balance, shares at Jul. 31, 2022	4,100	8,502,881		3,571,893
Purchases of common stock				$ (1,000)			(1,000)
Purchases of common stock, shares				70
Dividend declared at $0.65 per common share outstanding						(2,958,000)	(2,958,000)
Unrealized (loss), net of tax effect					(146,000)		(146,000)
Net Income						607,000	607,000
Ending balance, value at Oct. 31, 2022	$ 99,000	$ 850,000	1,934,000	$ (4,550,000)	(263,000)	49,382,000	47,452,000
Ending balance, shares at Oct. 31, 2022	4,100	8,502,881		3,571,963
Beginning balance, value at Apr. 30, 2023	$ 99,000	$ 850,000	1,934,000	$ (4,554,000)	(161,000)	52,481,000	50,649,000
Beginning balance, shares at Apr. 30, 2023	4,100	8,502,881		3,572,338
Purchases of common stock				$ (41,000)			(41,000)
Purchases of common stock, shares				3,750
Dividend declared at $0.65 per common share outstanding						(3,203,000)	(3,203,000)
Unrealized (loss), net of tax effect					(230,000)		(230,000)
Net Income						2,319,000	2,319,000
Ending balance, value at Oct. 31, 2023	$ 99,000	$ 850,000	1,934,000	$ (4,595,000)	(391,000)	51,597,000	49,494,000
Ending balance, shares at Oct. 31, 2023	4,100	8,502,881		3,576,088
Beginning balance, value at Jul. 31, 2023	$ 99,000	$ 850,000	1,934,000	$ (4,576,000)	(184,000)	54,855,000	52,978,000
Beginning balance, shares at Jul. 31, 2023	4,100	8,502,881		3,574,373
Purchases of common stock				$ (19,000)			(19,000)
Purchases of common stock, shares				1,715
Dividend declared at $0.65 per common share outstanding						(3,203,000)	(3,203,000)
Unrealized (loss), net of tax effect					(207,000)		(207,000)
Net Income						(55,000)	(55,000)
Ending balance, value at Oct. 31, 2023	$ 99,000	$ 850,000	$ 1,934,000	$ (4,595,000)	$ (391,000)	$ 51,597,000	$ 49,494,000
Ending balance, shares at Oct. 31, 2023	4,100	8,502,881		3,576,088