Statements of Shareholders' Equity (Unaudited) - USD ($)	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Mar. 31, 2021		4,833,232
Balance at Mar. 31, 2021		$ 48,332	$ 19,338,127	$ 1,101,119	$ 50,404,364	$ 70,891,942
Unrealized gain (loss) on marketable securities, net of tax				(90,165)		(90,165)
Net income					3,579,566	3,579,566
Total comprehensive income						3,489,401
Stock-based compensation			7,238			7,238
Cash dividends declared ($1.00 per share of common stock)					(4,833,232)	(4,833,232)
Balance (in shares) at Jun. 30, 2021	4,833,232
Balance at Jun. 30, 2021		$ 48,332	19,345,365	1,010,954	49,150,698	69,555,349
Balance (in shares) at Mar. 31, 2022		4,830,826
Balance at Mar. 31, 2022		$ 48,308	19,256,485	(318,120)	45,578,456	64,565,129	[1]
Unrealized gain (loss) on marketable securities, net of tax				(338,553)		(338,553)
Net income					4,140,116	4,140,116
Total comprehensive income						3,801,563
Stock-based compensation			7,134			7,134
Cash dividends declared ($1.00 per share of common stock)					(4,830,826)	(4,830,826)
Balance (in shares) at Jun. 30, 2022	4,830,826
Balance at Jun. 30, 2022		$ 48,308	$ 19,263,619	$ (656,673)	$ 44,887,746	$ 63,543,000

[1] The March 31, 2021 Balance Sheet is derived from the audited financial statements contained in our Annual Report on Form 10-K for the fiscal year ended March 31, 2021.