Summary of Restricted Stock Units Activity (Detail) - $ / shares		1 Months Ended		12 Months Ended
		May 31, 2021	May 31, 2020	Mar. 31, 2022		Mar. 31, 2021	Mar. 31, 2020
Number of Shares
Granted		25,172	30,881
Restricted Stock Units
Number of Shares
Beginning Balance				301,000
Granted	[1]			172,000
Vested				(133,000)
Forfeited				(33,000)
Ending Balance				307,000		301,000
Weighted Average Grant Date Fair Value
Beginning Balance				$ 273.57
Granted				288.77	[1]	$ 254.8	$ 258.6
Vested				296.88
Forfeited				274.55
Ending Balance				$ 274.32		$ 273.57

[1] Includes approximately 11,000 performance-based awards granted due to greater than 100% target vesting.