Note L - Stockholders' Equity - Schedule of Stockholders' Equity (Details) - USD ($)	3 Months Ended				6 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance		$ 66,865,367			$ 66,865,367
Net earnings (loss)	$ (250,005)		$ (1,544,137)		(1,108,867)	$ (1,349,365)
Repurchase of shares	(410,221)
Balance	65,281,496				65,281,496
Common Stock [Member]
Balance	8,306,160	8,295,160	8,225,160	$ 8,205,160	8,295,160	8,205,160
Net earnings (loss)
Issuance of restricted stock		11,000		20,000
Paid in capital – restricted stock awards
Cash dividends
Repurchase of shares
Balance	8,306,160	8,306,160	8,225,160	8,225,160	8,306,160	8,225,160
Additional Paid-in Capital [Member]
Balance	29,665,230	29,565,416	29,385,708	29,322,472	29,565,416	29,322,472
Net earnings (loss)
Issuance of restricted stock
Paid in capital – restricted stock awards	110,813	99,814	83,236	63,236
Cash dividends
Repurchase of shares
Balance	29,776,043	29,665,230	29,468,944	29,385,708	29,776,043	29,468,944
Treasury Stock [Member]
Balance	(5,525,964)	(5,525,964)	(5,525,964)	(5,525,964)	(5,525,964)	(5,525,964)
Net earnings (loss)
Issuance of restricted stock
Paid in capital – restricted stock awards
Cash dividends
Repurchase of shares	(410,221)
Balance	(5,936,185)	(5,525,964)	(5,525,964)	(5,525,964)	(5,936,185)	(5,525,964)
Retained Earnings [Member]
Balance	33,528,664	34,530,755	40,394,703	40,479,909	34,530,755	40,479,909
Net earnings (loss)	(250,005)	(858,862)	(1,544,137)	194,772
Issuance of restricted stock
Paid in capital – restricted stock awards
Cash dividends	(143,181)	(143,229)	(139,990)	(279,978)
Repurchase of shares
Balance	$ 33,135,478	$ 33,528,664	$ 38,710,576	$ 40,394,703	$ 33,135,478	$ 38,710,576