CONDENSED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance at Feb. 28, 2018	$ 2,418,400	$ 8,573,300	$ 20,714,500	$ (11,304,100)	$ 20,402,100
Balance (in Shares) at Feb. 28, 2018	12,092,080			3,912,468
Purchases of treasury stock				$ (29,600)	(29,600)
Purchases of treasury stock (in Shares)				2,846
Sales of treasury stock				$ 25,100	25,100
Sales of treasury stock (in Shares)				(3,302)
Dividends declared			(409,000)		(409,000)
Net earnings			1,816,600		1,816,600
Balance at May. 31, 2018	$ 2,418,400	8,573,300	22,122,100	$ (11,308,600)	21,805,200
Balance (in Shares) at May. 31, 2018	12,092,080			3,912,012
Balance at Feb. 28, 2018	$ 2,418,400	8,573,300	20,714,500	$ (11,304,100)	20,402,100
Balance (in Shares) at Feb. 28, 2018	12,092,080			3,912,468
Net earnings					6,122,900
Balance at Nov. 30, 2018	$ 2,418,400	8,828,600	25,609,600	$ (11,108,900)	25,747,700
Balance (in Shares) at Nov. 30, 2018	12,092,080			3,888,961
Balance at May. 31, 2018	$ 2,418,400	8,573,300	22,122,100	$ (11,308,600)	21,805,200
Balance (in Shares) at May. 31, 2018	12,092,080			3,912,012
Exercise of options				$ 77,200	77,200
Exercise of options (in Shares)				(9,634)
Share-based compensation expense		70,000			70,000
Net earnings			1,490,700		1,490,700
Balance at Aug. 31, 2018	$ 2,418,400	8,643,300	23,612,800	$ (11,231,400)	23,443,100
Balance (in Shares) at Aug. 31, 2018	12,092,080			3,902,378
Purchases of treasury stock				$ (2,300)	(2,300)
Purchases of treasury stock (in Shares)				233
Sales of treasury stock				$ 124,800	124,800
Sales of treasury stock (in Shares)				(13,650)
Dividends declared			(818,800)		(818,800)
Share-based compensation expense		185,300			185,300
Net earnings			2,815,600		2,815,600
Balance at Nov. 30, 2018	$ 2,418,400	8,828,600	25,609,600	$ (11,108,900)	25,747,700
Balance (in Shares) at Nov. 30, 2018	12,092,080			3,888,961
Balance at Feb. 28, 2019	$ 2,418,400	8,975,100	25,754,900	$ (11,217,900)	25,930,500
Balance (in Shares) at Feb. 28, 2019	12,092,080			3,896,998
Purchases of treasury stock				$ (302,500)	(302,500)
Purchases of treasury stock (in Shares)				36,959
Sales of treasury stock		68,100		$ 54,300	122,400
Sales of treasury stock (in Shares)				(19,171)
Dividends declared			(408,900)		(408,900)
Share-based compensation expense		166,300			166,300
Net earnings			1,363,600		1,363,600
Balance at May. 31, 2019	$ 2,418,400	9,209,500	26,709,600	$ (11,466,100)	26,871,400
Balance (in Shares) at May. 31, 2019	12,092,080			3,914,786
Balance at Feb. 28, 2019	$ 2,418,400	8,975,100	25,754,900	$ (11,217,900)	25,930,500
Balance (in Shares) at Feb. 28, 2019	12,092,080			3,896,998
Net earnings					5,107,000
Balance at Nov. 30, 2019	$ 2,480,000	9,603,400	29,607,200	$ (12,279,300)	29,411,300
Balance (in Shares) at Nov. 30, 2019	12,400,080			4,012,064
Balance at May. 31, 2019	$ 2,418,400	9,209,500	26,709,600	$ (11,466,100)	26,871,400
Balance (in Shares) at May. 31, 2019	12,092,080			3,914,786
Purchases of treasury stock				$ (417,100)	(417,100)
Purchases of treasury stock (in Shares)				60,357
Sales of treasury stock		54,000		$ 54,600	108,600
Sales of treasury stock (in Shares)				(22,961)
Dividends declared			(422,300)		(422,300)
Share-based compensation expense		166,200			166,200
Issuance of restricted share awards for vesting	$ 61,600	(61,600)
Issuance of restricted share awards for vesting (in Shares)	308,000
Net earnings			1,007,600		1,007,600
Balance at Aug. 31, 2019	$ 2,480,000	9,368,100	27,294,900	$ (11,828,600)	27,314,400
Balance (in Shares) at Aug. 31, 2019	12,400,080			3,952,182
Purchases of treasury stock				$ (534,100)	(534,100)
Purchases of treasury stock (in Shares)				84,841
Sales of treasury stock		69,000		$ 83,400	152,400
Sales of treasury stock (in Shares)				(24,959)
Dividends declared			(423,500)		(423,500)
Share-based compensation expense		166,300			166,300
Net earnings			2,735,800		2,735,800
Balance at Nov. 30, 2019	$ 2,480,000	$ 9,603,400	$ 29,607,200	$ (12,279,300)	$ 29,411,300
Balance (in Shares) at Nov. 30, 2019	12,400,080			4,012,064