Stock Options and Stock-Based Compensation - Stock Options (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding, beginning balance	1,163,179	1,115,984	1,100,952
Options granted, Shares	276,275	241,625	441,550
Options exercised, Shares	(200,753)	(111,758)	(310,729)
Options cancelled /forfeited , Shares	(123,236)	(82,672)	(115,789)
Options outstanding, ending balance	1,115,465	1,163,179	1,115,984
Options granted, weighted average exercise price	$ 35.51	$ 37.64	$ 33.06
Options exercised, weighted average exercise price	19.75	17.27	15.31
Options cancelled /forfeited, weighted average exercise price	33.44	32.31	23.33
Weighted average exercise price per share	$ 30.36	$ 27.65	$ 24.80
Options available for future grants	650,345	800,342	959,295
Exercisable options	529,691	559,168	430,294
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price range of outstanding options	$ 45.55	$ 45.55	$ 45.55
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price range of outstanding options	$ 9.05	$ 7.78	$ 7.78