Benefit Plans (Option activity) (Details) - Stock Options Plans - USD ($)	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Shares
Options outstanding, beginning of year (in shares)	314,742
Granted (in shares)	2,598
Exercised (in shares)	(34,649)
Forfeited (in shares)	(11,836)
Expired (in shares)	(2,908)
Options outstanding, end of period (in shares)	267,947	314,742
Options exercisable, end of period (in shares)	117,979
Weighted Average Exercise Price
Options outstanding, beginning of year (in dollars per share)	$ 104.41
Granted (in dollars per share)	124.67
Exercised (in dollars per share)	82.77
Forfeited (in dollars per share)	128.08
Expired (in dollars per share)	159.05
Options outstanding, end of period (in dollars per share)	105.77	$ 104.41
Options exercisable, end of period (in dollars per share)	$ 108.47
Stock Option Activity Additional Disclosures
Weighted-average remaining contractual term, options outstanding, end of period	5 years
Weighted-average remaining contractual terms, options exercisable, end of period	4 years 11 months 4 days
Aggregate intrinsic value, options outstanding, end of period	$ 11,130,937
Aggregate intrinsic value, options exercisable, end of period	4,758,782
Intrinsic value of options exercised	1,556,871	$ 493,418	$ 17,494,865
Tax benefit of options exercised	$ 120,557	$ 51,103	$ 2,454,039