Stock-Based Compensation and Stock Options - Stock Options (Detail) - $ / shares	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning balance, Shares	1,058,411	1,064,439
Options granted, Shares	47,025	56,800
Options exercised, Shares	(100,955)	(54,238)
Options cancelled/forfeited, Shares	(3,651)	(3,747)
Options outstanding, ending balance, Shares	1,000,830	1,063,254
Options outstanding, beginning balance, Weighted Average Exercise Price	$ 45.17	$ 39.45
Options granted, Weighted Average Exercise Price	70.24	49.40
Options exercised, Weighted Average Exercise Price	38.01	30.84
Options cancelled/forfeited, Weighted Average Exercise Price	51.43	39.76
Options outstanding, ending balance, Weighted Average Exercise Price	$ 47.05	$ 40.43