v3.7.0.1
Stock Based Compensation Stock-Based Compensation - Summary of Assumptions Used for Market Share Units (Details) - $ / shares
12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Options 451,668    
Weighted Average Remaining Contractual Life 8 years 4 months 24 days    
Weighted Average Exercise Price $ 62.29    
Performance Market Units [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 0.94% 1.00% 0.87%
Dividend yield 0.00% 0.00% 0.00%
Time of maturity, in years 3 years 3 years 3 years
Expected volatility 31.74% 25.52% 30.83%
Market Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.41% 1.79% 1.94%
Dividend yield 1.22% 1.02% 1.00%
Time of maturity, in years 6 years 6 years 6 years
Expected volatility 30.40% 32.75% 40.48%
$15.01-$20.00      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Options 5,122    
Weighted Average Remaining Contractual Life 6 days    
Weighted Average Exercise Price $ 18.34    
$55.01-$60.00      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Options 242,068    
Weighted Average Remaining Contractual Life 9 years 1 month 6 days    
Weighted Average Exercise Price $ 57.60    
$65-01-$69.85      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Options 204,478    
Weighted Average Remaining Contractual Life 7 years 8 months 12 days    
Weighted Average Exercise Price $ 68.94