Allowance for Loan Losses and Credit Quality Indicators (Summary of Past Due Receivables) (Details) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Fiscal Year End Date	--03-31
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	$ 57,200,000	$ 47,000,000.0	$ 42,300,000
Financing Receivable, Percent Past Due	10.50%	9.00%	8.30%
Total	$ 127,327,689	$ 101,157,090	$ 83,428,597
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	48,206,910	35,992,122	29,356,319
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	28,450,942	22,393,106	19,523,845
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 50,669,837	$ 42,771,862	$ 34,548,433
Contractual basis [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Percent Past Due	12.80%	11.40%	10.70%
Total	$ 154,877,754	$ 128,483,509	$ 107,791,448
Contractual basis [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	49,137,102	40,300,574	32,959,151
Contractual basis [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	35,020,925	28,549,394	24,812,730
Contractual basis [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 70,719,727	$ 59,633,541	$ 50,019,567