Note J - Stockholders' Equity - Schedule of Stockholders' Equity (Details) - USD ($)	3 Months Ended						9 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018
Balance			$ 72,481,577				$ 72,481,577
Net earnings (loss)	$ (881,003)			$ 664,773			(2,230,368)	$ 6,265,582
Balance	69,940,956						69,940,956
Common Stock [Member]
Balance	8,225,160	$ 8,225,160	8,205,160	8,185,160	$ 8,185,160	$ 8,185,160	8,205,160	8,185,160
Net earnings (loss)
Issuance of restricted stock			20,000
Paid in capital – restricted stock awards
Cash dividends
Balance	8,225,160	8,225,160	8,225,160	8,185,160	8,185,160	8,185,160	8,225,160	8,185,160
Additional Paid-in Capital [Member]
Balance	29,468,944	29,385,708	29,322,472	29,299,354	29,227,114	29,154,874	29,322,472	29,154,874
Net earnings (loss)
Issuance of restricted stock
Paid in capital – restricted stock awards	83,236	83,236	63,236	72,240	72,240	72,240
Cash dividends
Balance	29,552,180	29,468,944	29,385,708	29,371,594	29,299,354	29,227,114	29,552,180	29,371,594
Treasury Stock [Member]
Balance	(5,525,964)	(5,525,964)	(5,525,964)	(5,475,964)	(5,475,964)	(5,475,964)	(5,525,964)	(5,475,964)
Net earnings (loss)
Issuance of restricted stock
Paid in capital – restricted stock awards
Cash dividends
Balance	(5,525,964)	(5,525,964)	(5,525,964)	(5,475,964)	(5,475,964)	(5,475,964)	(5,525,964)	(5,475,964)
Retained Earnings [Member]
Balance	38,710,576	40,394,703	40,479,909	41,681,339	40,100,990	36,711,380	40,479,909	36,711,380
Net earnings (loss)	(881,003)	(1,544,137)	194,772	664,773	2,000,916	3,599,893
Issuance of restricted stock
Paid in capital – restricted stock awards
Cash dividends	(139,993)	(139,990)	(279,978)	(420,567)	(420,567)	(210,283)
Balance	$ 37,689,580	$ 38,710,576	$ 40,394,703	$ 41,925,545	$ 41,681,339	$ 40,100,990	$ 37,689,580	$ 41,925,545