Stock Options and Stock-Based Compensation - Stock Options (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, beginning balance, Shares	651,857	723,876	937,158
Options granted, Shares	59,900	168,300	130,200
Options exercised, Shares	(201,293)	(209,301)	(298,570)
Options cancelled/forfeited, Shares	(20,737)	(31,018)	(44,912)
Options outstanding, ending balance, Shares	489,727	651,857	723,876
Options granted, weighted average exercise price	$ 206.76	$ 159.43	$ 161.95
Options exercised, weighted average exercise price	80.3	63.21	55.44
Options cancelled/forfeited, weighted average exercise price	157.84	140.38	79.3
Weighted average exercise price per share	$ 129.39	$ 108.1	$ 84.55
Options available for future grants	618,809	657,972	805,097
Exercisable options	269,253	319,703	354,460
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price range of outstanding options	$ 33.16	$ 33.16	$ 22.07
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price range of outstanding options	$ 235.34	$ 197.16	$ 197.16