Benefit Plans (Option activity) (Details) - Stock Options Plans - USD ($)	12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Options Activity [Roll Forward]
Options outstanding, beginning of year (in shares)	348,743
Granted (in shares)	16,490
Exercised (in shares)	(8,523)
Forfeited (in shares)	(21,523)
Expired (in shares)	(20,445)
Options outstanding, end of period (in shares)	314,742	348,743
Options exercisable, end of period (in shares)	114,757
Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning of year (in dollars per share)	$ 104.38
Granted (in dollars per share)	96.07
Exercised (in dollars per share)	84.84
Forfeited (in dollars per share)	119.93
Expired (in dollars per share)	88.88
Options outstanding, end of period (in dollars per share)	104.41	$ 104.38
Options exercisable, end of period (in dollars per share)	$ 100.22
Stock Option Activity Additional Disclosures
Weighted-average remaining contractual term, Options outstanding, end of period	5 years 9 months 25 days
Weighted-average remaining contractual terms, Options exercisable, end of period	5 years 25 days
Aggregate intrinsic value, Options outstanding, end of period	$ 589,526
Aggregate intrinsic value, Options exercisable, end of period	441,097
Intrinsic value of options exercised	$ 493,418	$ 17,494,865	$ 9,996,167