Allowance for Loan Losses and Credit Quality Indicators (Summary of Past Due Receivables) (Details) - USD ($)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Fiscal Year End Date	--03-31
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	$ 47,000,000	$ 42,300,000	$ 37,500,000
Financing Receivable, Percent Past Due	9.70%	9.00%	8.40%
Total	$ 101,157,090	$ 83,428,597	$ 73,864,728
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	35,992,122	29,356,319	27,004,856
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	22,393,106	19,523,845	17,671,790
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 42,771,862	$ 34,548,433	$ 29,188,082
Contractual basis [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Percent Past Due	11.40%	10.70%	10.30%
Total	$ 128,483,509	$ 107,791,448	$ 96,964,281
Contractual basis [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	40,300,574	32,959,151	30,640,748
Contractual basis [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	28,549,394	24,812,730	23,002,999
Contractual basis [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 59,633,541	$ 50,019,567	$ 43,320,534