STATEMENTS OF SHAREHOLDERS' EQUITY (Unaudited) - USD ($)	Common Stock	Additional Paid-in Capital	AOCI Including Portion Attributable to Noncontrolling Interest	Retained Earnings	Total
Equity Balance, Starting at Mar. 31, 2022	$ 48,308	$ 19,256,485	$ (318,120)	$ 45,578,456	$ 64,565,129
Shares Outstanding, Starting at Mar. 31, 2022	4,830,826
Unrealized loss from marketable securities, net of tax			(338,553)		(338,553)
Net income				4,140,116	4,140,116
Total comprehensive income					3,801,563
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		7,134			7,134
Cash dividends declared ($1.00 per share of common stock)				(4,830,826)	(4,830,826)
Shares Outstanding, Ending at Jun. 30, 2022	4,830,826
Equity Balance, Ending at Jun. 30, 2022	$ 48,308	19,263,619	(656,673)	44,887,746	63,543,000
Equity Balance, Starting at Mar. 31, 2022	$ 48,308	19,256,485	(318,120)	45,578,456	64,565,129
Shares Outstanding, Starting at Mar. 31, 2022	4,830,826
Unrealized loss from marketable securities, net of tax					(1,133,242)
Net income					14,461,814
Total comprehensive income					13,328,572
Shares Outstanding, Ending at Dec. 31, 2022	4,830,826
Equity Balance, Ending at Dec. 31, 2022	$ 48,308	19,310,703	(1,451,362)	45,547,791	63,455,440
Equity Balance, Starting at Jun. 30, 2022	$ 48,308	19,263,619	(656,673)	44,887,746	63,543,000
Shares Outstanding, Starting at Jun. 30, 2022	4,830,826
Unrealized loss from 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
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		39,951			39,951
Cash dividends declared ($1.00 per share of common stock)				(4,830,826)	(4,830,826)
Shares Outstanding, Ending at Sep. 30, 2022	4,830,826
Equity Balance, Ending at Sep. 30, 2022	$ 48,308	19,303,570	(1,784,035)	46,147,293	63,715,136
Unrealized loss from marketable securities, net of tax			332,673		332,673
Net income				4,231,324	4,231,324
Total comprehensive income					4,563,997
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		7,133			7,133
Cash dividends declared ($1.00 per share of common stock)				(4,830,826)	(4,830,826)
Shares Outstanding, Ending at Dec. 31, 2022	4,830,826
Equity Balance, Ending at Dec. 31, 2022	$ 48,308	19,310,703	(1,451,362)	45,547,791	63,455,440
Equity Balance, Starting at Mar. 31, 2023	$ 48,308	19,295,442	(1,213,858)	48,949,610	67,079,502
Shares Outstanding, Starting at Mar. 31, 2023	4,830,826
Stock Issued During Period, Value, Stock Options Exercised	$ 26	117,501			117,527
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period	2,575
Unrealized loss from marketable securities, net of tax			(234,701)		(234,701)
Net income				4,403,730	4,403,730
Total comprehensive income					4,169,029
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		10,536			10,536
Cash dividends declared ($1.00 per share of common stock)				(4,830,826)	(4,830,826)
Shares Outstanding, Ending at Jun. 30, 2023	4,833,401
Equity Balance, Ending at Jun. 30, 2023	$ 48,334	19,423,479	(1,448,559)	48,522,514	66,545,768
Equity Balance, Starting at Mar. 31, 2023	$ 48,308	19,295,442	(1,213,858)	48,949,610	67,079,502
Shares Outstanding, Starting at Mar. 31, 2023	4,830,826
Unrealized loss from marketable securities, net of tax					460,541
Net income					13,311,718
Total comprehensive income					13,772,259
Shares Outstanding, Ending at Dec. 31, 2023	4,833,401
Equity Balance, Ending at Dec. 31, 2023	$ 48,334	19,542,335	(753,317)	47,763,700	66,601,052
Equity Balance, Starting at Jun. 30, 2023	$ 48,334	19,423,479	(1,448,559)	48,522,514	66,545,768
Shares Outstanding, Starting at Jun. 30, 2023	4,833,401
Unrealized loss from marketable securities, net of tax			(53,588)		(53,588)
Net income				4,723,566	4,723,566
Total comprehensive income					4,669,978
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		106,312			106,312
Cash dividends declared ($1.00 per share of common stock)				(4,833,401)	(4,833,401)
Shares Outstanding, Ending at Sep. 30, 2023	4,833,401
Equity Balance, Ending at Sep. 30, 2023	$ 48,334	19,529,791	(1,502,147)	48,412,679	66,488,657
Unrealized loss from marketable securities, net of tax			748,830		748,830
Net income				4,184,422	4,184,422
Total comprehensive income					4,933,252
Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture		12,544			12,544
Cash dividends declared ($1.00 per share of common stock)				(4,833,401)	(4,833,401)
Shares Outstanding, Ending at Dec. 31, 2023	4,833,401
Equity Balance, Ending at Dec. 31, 2023	$ 48,334	$ 19,542,335	$ (753,317)	$ 47,763,700	$ 66,601,052