Stock-Based Compensation and Stock Options - Stock Options (Detail) - $ / shares	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning balance	1,102,919	1,135,586	1,115,465	1,163,179
Options granted, Shares	143,750	155,275	234,250	242,275
Options exercised, Shares	(4,256)	(44,077)	(95,472)	(139,718)
Options cancelled/forfeited, Shares	(3,550)	(15,986)	(15,380)	(34,938)
Options outstanding, ending balance	1,238,863	1,230,798	1,238,863	1,230,798
Options outstanding, beginning, Weighted Average Exercise Price	$ 32.17	$ 28.81	$ 29.67	$ 27.65
Options granted, Weighted Average Exercise Price	32.10	34.78	36.90	34.44
Options exercised, Weighted Average Exercise Price	25.86	23.75	22.05	19.64
Options cancelled/forfeited, Weighted Average Exercise Price	37.17	34.64	36.55	35.63
Options outstanding, ending, Weighted Average Exercise Price	$ 32.17	$ 29.67	$ 32.17	$ 29.67