v3.7.0.1
Debt - Long Term Debt (Phantom) (Detail)
12 Months Ended
Mar. 31, 2017
Apr. 23, 2015
Senior Unsecured 3.375% Convertible Notes Due 2038    
Debt Instrument [Line Items]    
Interest rate of debt instrument 3.375% 3.375%
Maturity year 2038  
2011 Credit Facility Due 2018    
Debt Instrument [Line Items]    
Maturity year 2018