Stock-Based Compensation - Summary of Changes in Restricted Stock Units and Market Share Units (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Granted	$ 58.05	$ 75.32	$ 73.39
Restricted Stock Units (RSUs)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	721,647
Number of RSU and MSU, Granted	342,930
Number of RSU and MSU, Stock dividend	9,108
Number of RSU and MSU, Vested	(169,486)
Number of RSU and MSU, cancelled	(23,864)
Number of RSU and MSU, Non-vested awards, Ending Balance	880,335	721,647
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 57.72
Weighted Average Grant Date Fair Value, Granted	58.05
Weighted Average Grant Date Fair Value, Stock dividend	55.83
Weighted Average Grant Date Fair Value, Vested	70.18
Weighted Average Grant Date Fair Value, Canceled	69.56
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 55.61	$ 57.72
Market Share Unit Number (MSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	352,584
Number of RSU and MSU, Granted	51,063
Number of RSU and MSU, Stock dividend	2,226
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	(172,314)
Number of RSU and MSU, cancelled	(24,839)
Number of RSU and MSU, Non-vested awards, Ending Balance	208,720	352,584
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 72.83
Weighted Average Grant Date Fair Value, Granted	62.00
Weighted Average Grant Date Fair Value, Stock dividend	81.97
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	59.95
Weighted Average Grant Date Fair Value, Canceled	74.83
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 80.78	$ 72.83
Performance condition-based Share Units (PSU)
Number of RSU and MSU
Number of RSU and MSU, Non-vested awards, Beginning Balance	42,526
Number of RSU and MSU, Granted	62,512
Number of RSU and MSU, Stock dividend	990
Number of RSU and MSU, Performance factor	0
Number of RSU and MSU, Vested	0
Number of RSU and MSU, cancelled	(4,898)
Number of RSU and MSU, Non-vested awards, Ending Balance	101,130	42,526
Weighted average grant date fair value
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance	$ 68.48
Weighted Average Grant Date Fair Value, Granted	50.65
Weighted Average Grant Date Fair Value, Stock dividend	58.74
Weighted Average Grant Date Fair Value, Performance factor	0
Weighted Average Grant Date Fair Value, Vested	0
Weighted Average Grant Date Fair Value, Canceled	65.78
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance	$ 57.49	$ 68.48