STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Beginning balance, value at Mar. 31, 2022	$ 48,308	$ 19,256,485	$ (318,120)	$ 45,578,456	$ 64,565,129
Beginning balance (in shares) at Mar. 31, 2022	4,830,826
Comprehensive income:
Unrealized 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)
Ending balance, value at Jun. 30, 2022	$ 48,308	19,263,619	(656,673)	44,887,746	63,543,000
Ending balance (in shares) at Jun. 30, 2022	4,830,826
Beginning balance, value at Mar. 31, 2022	$ 48,308	19,256,485	(318,120)	45,578,456	64,565,129
Beginning balance (in shares) at Mar. 31, 2022	4,830,826
Comprehensive income:
Net income					10,230,490
Total comprehensive income					8,764,575
Ending balance, value at Sep. 30, 2022	$ 48,308	19,303,570	(1,784,035)	46,147,293	63,715,136
Ending balance (in shares) at Sep. 30, 2022	4,830,826
Beginning balance, value at Jun. 30, 2022	$ 48,308	19,263,619	(656,673)	44,887,746	63,543,000
Beginning balance (in shares) at Jun. 30, 2022	4,830,826
Comprehensive income:
Unrealized loss on marketable securities, net of tax			(1,127,362)		(1,127,362)
Net income				6,090,373	6,090,373
Total comprehensive income					4,963,011
Stock-based compensation		39,951			39,951
Cash dividends declared ($1.00 per share of common stock)				(4,830,826)	(4,830,826)
Ending balance, value at Sep. 30, 2022	$ 48,308	19,303,570	(1,784,035)	46,147,293	63,715,136
Ending balance (in shares) at Sep. 30, 2022	4,830,826
Beginning balance, value at Mar. 31, 2023	$ 48,308	19,295,442	(1,213,858)	48,949,610	67,079,502	[1]
Beginning balance (in shares) at Mar. 31, 2023	4,830,826
Exercise of stock options	$ 26	117,501			117,527
Exercise of stock options (in shares)	2,575
Comprehensive income:
Unrealized loss on marketable securities, net of tax			(234,701)		(234,701)
Net income				4,403,730	4,403,730
Total comprehensive income					4,169,029
Stock-based compensation		10,536			10,536
Cash dividends declared ($1.00 per share of common stock)				(4,830,826)	(4,830,826)
Ending balance, value at Jun. 30, 2023	$ 48,334	19,423,479	(1,448,559)	48,522,514	66,545,768
Ending balance (in shares) at Jun. 30, 2023	4,833,401
Beginning balance, value at Mar. 31, 2023	$ 48,308	19,295,442	(1,213,858)	48,949,610	67,079,502	[1]
Beginning balance (in shares) at Mar. 31, 2023	4,830,826
Comprehensive income:
Net income					9,127,296
Total comprehensive income					8,839,007
Ending balance, value at Sep. 30, 2023	$ 48,334	19,529,791	(1,502,147)	48,412,679	66,488,657
Ending balance (in shares) at Sep. 30, 2023	4,833,401
Beginning balance, value at Jun. 30, 2023	$ 48,334	19,423,479	(1,448,559)	48,522,514	66,545,768
Beginning balance (in shares) at Jun. 30, 2023	4,833,401
Comprehensive income:
Unrealized loss on marketable securities, net of tax			(53,588)		(53,588)
Net income				4,723,566	4,723,566
Total comprehensive income					4,669,978
Stock-based compensation		106,312			106,312
Cash dividends declared ($1.00 per share of common stock)				(4,833,401)	(4,833,401)
Ending balance, value at Sep. 30, 2023	$ 48,334	$ 19,529,791	$ (1,502,147)	$ 48,412,679	$ 66,488,657
Ending balance (in shares) at Sep. 30, 2023	4,833,401

[1] The March 31, 2023 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, 2023.