v3.7.0.1
Stock-Based Compensation - Summary of Changes in Restricted Stock Units and Market Share Units (Detail)
12 Months Ended
Mar. 31, 2017
$ / shares
shares
Restricted Stock Units (RSUs)  
Number of RSU and MSU  
Number of RSU and MSU, Non-vested awards, Beginning Balance | shares 502,440
Number of RSU and MSU, Granted | shares 264,305
Number of RSU and MSU, Stock dividend | shares 5,943
Number of RSU and MSU, Vested | shares (160,453)
Number of RSU and MSU, cancelled | shares (11,960)
Number of RSU and MSU, Non-vested awards, Ending Balance | shares 600,275
Weighted average grant date fair value  
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance | $ / shares $ 51.26
Weighted Average Grant Date Fair Value, Granted | $ / shares 56.40
Weighted Average Grant Date Fair Value, Stock dividend | $ / shares 51.82
Weighted Average Grant Date Fair Value, Vested | $ / shares 50.63
Weighted Average Grant Date Fair Value, Canceled | $ / shares 63.02
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance | $ / shares $ 51.96
Market Share Unit Number (MSU)  
Number of RSU and MSU  
Number of RSU and MSU, Non-vested awards, Beginning Balance | shares 548,946
Number of RSU and MSU, Granted | shares 83,720
Number of RSU and MSU, Stock dividend | shares 4,357
Number of RSU and MSU, Performance factor | shares 45,065
Number of RSU and MSU, Vested | shares (232,947)
Number of RSU and MSU, cancelled | shares 0
Number of RSU and MSU, Non-vested awards, Ending Balance | shares 449,141
Weighted average grant date fair value  
Weighted Average Grant Date Fair Value, Non-vested awards, Beginning Balance | $ / shares $ 64.46
Weighted Average Grant Date Fair Value, Granted | $ / shares 70.79
Weighted Average Grant Date Fair Value, Stock dividend | $ / shares 65.41
Weighted Average Grant Date Fair Value, Performance factor | $ / shares 65.03
Weighted Average Grant Date Fair Value, Vested | $ / shares 65.03
Weighted Average Grant Date Fair Value, Canceled | $ / shares 0
Weighted Average Grant Date Fair Value, Non-vested awards, Ending Balance | $ / shares $ 65.41