STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	Common Stock	Additional Paid-in Capital	AOCI Including Portion Attributable to Noncontrolling Interest	Retained Earnings	Total
Equity Balance, Starting at Mar. 31, 2021	$ 48,332	$ 19,338,127	$ 1,101,119	$ 50,404,364	$ 70,891,942
Shares Outstanding, Starting at Mar. 31, 2021	4,833,232
Repurchase of common stock	$ (29)	(163,492)			(163,521)
Repurchase of common stock	(2,888)
Stock Issued During Period, Value, Stock Options Exercised	$ 5	(5)			$ 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period	482				5,000
Unrealized gain (loss) from marketable securities, net of tax			(1,419,239)		$ (1,419,239)
Net income				14,507,501	14,507,501
Total comprehensive income					13,088,262
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		81,855			81,855
Cash dividends declared ($4.00 per share of common stock)				(19,333,409)	(19,333,409)
Shares Outstanding, Ending at Mar. 31, 2022	4,830,826
Equity Balance, Ending at Mar. 31, 2022	$ 48,308	19,256,485	(318,120)	45,578,456	64,565,129
Repurchase of common stock	$ (3)	(20,697)			(20,700)
Repurchase of common stock	(264)
Stock Issued During Period, Value, Stock Options Exercised	$ 3	(3)			$ 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period	264				1,000
Unrealized gain (loss) from marketable securities, net of tax			(895,738)		$ (895,738)
Net income				22,694,458	22,694,458
Total comprehensive income					21,798,720
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		59,657			59,657
Cash dividends declared ($4.00 per share of common stock)				(19,323,304)	(19,323,304)
Shares Outstanding, Ending at Mar. 31, 2023	4,830,826
Equity Balance, Ending at Mar. 31, 2023	$ 48,308	$ 19,295,442	$ (1,213,858)	$ 48,949,610	$ 67,079,502