Benefit Plans (Restricted stock) (Details) - Restricted Stock - $ / shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Shares
Outstanding at beginning of period (in shares)	460,614
Granted during the period (in shares)	3,993	3,250	4,062
Vested during the period (in shares)	(62,983)
Forfeited during the period (in shares)	(13,047)
Outstanding at end of period (in shares)	388,577	460,614
Weighted Average Fair Value at Grant Date
Outstanding at beginning of period (in dollars per share)	$ 101.82
Granted during the period (in dollars per share)	120.12	$ 129.85	$ 188.38
Vested during the period (in dollars per share)	103.85
Forfeited during the period (in dollars per share)	116.56
Outstanding at end of period (in dollars per share)	$ 101.18	$ 101.82