Marketable Securities: Gross unrealized holding losses and estimated fair value of marketable securities for which an allowance for credit losses has not been recorded (Details) - USD ($)	Jun. 30, 2023	Mar. 31, 2023
Estimated Fair Value	$ 36,594,686	$ 37,084,628
Gross Unrealized Holding Losses	(934,611)	(590,967)
Estimated Fair Value	15,298,420	13,294,817
Gross Unrealized Holding Losses	(919,664)	(963,879)
Estimated Fair Value	51,893,106	50,379,445
Gross Unrealized Holding Losses	(1,854,275)	(1,554,846)
Corporate Bond Securities
Estimated Fair Value	36,594,686	37,084,628
Gross Unrealized Holding Losses	(934,611)	(590,967)
Estimated Fair Value	15,298,420	13,294,817
Gross Unrealized Holding Losses	(919,664)	(963,879)
Estimated Fair Value	51,893,106	50,379,445
Gross Unrealized Holding Losses	$ (1,854,275)	$ (1,554,846)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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