XML 65 R48.htm IDEA: XBRL DOCUMENT v3.3.1.900
Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted (Detail) - Stock Options - $ / shares
3 Months Ended 9 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]        
Weighted average grant-date fair value $ 34.05 $ 15.36 $ 28.91 $ 9.18
Valuation assumptions:        
Risk-free interest rate 1.50% 1.70% 1.60% 1.60%
Expected option life (years) 4 years 1 month 24 days 4 years 2 months 1 day 4 years 1 month 21 days 4 years 2 months 9 days
Expected volatility 49.60% 49.70% 49.70% 49.30%