Allowance for Credit Losses and Credit Quality Information (Rollforward of Allowance For Loan Losses) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				$ 96,487,856				$ 81,519,624	$ 96,487,856	$ 81,519,624	$ 66,088,139
Provision for credit losses	$ 5,636,000	$ 28,857,000	$ 26,090,000	25,661,000	$ 32,252,000	$ 55,219,000	$ 52,968,000	41,291,000	86,244,714	181,730,182	148,426,578
Loan losses									(141,270,125)	(183,439,199)	(148,308,199)
Recoveries									21,631,475	16,677,249	15,313,106
Ending Balance	$ 91,722,288				96,487,856				91,722,288	96,487,856	81,519,624
Impact of ASC 326 adoption
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				$ 28,628,368				$ 0	$ 28,628,368	0	0
Ending Balance					$ 28,628,368					$ 28,628,368	$ 0