Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Fair Value Measurements - Summary of Company's Financial Assets and Liabilities that were Accounted for at Fair Value on Recurring Basis (Detail)

v2.4.0.8
Fair Value Measurements - Summary of Company's Financial Assets and Liabilities that were Accounted for at Fair Value on Recurring Basis (Detail) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2014
Mar. 31, 2013
Assets    
Interest rate swap contracts included in Accounts Payable $ 0.5 $ 1.3
Fair Value Measurements, Recurring [Member]
    
Assets    
Cash and cash equivalents 167.5  
Restricted cash and cash equivalents 65.2  
Restricted short-term investments 0.1  
Total Assets 235.1  
Interest rate swap contracts included in Accounts Payable 0.5  
Total Liabilities 0.5  
Fair Value Measurements, Recurring [Member] | Forward contracts [Member]
    
Assets    
Forward contracts included in Other Assets 2.3  
Level 1 [Member] | Fair Value Measurements, Recurring [Member]
    
Assets    
Cash and cash equivalents 167.5  
Restricted cash and cash equivalents 65.2  
Restricted short-term investments     
Total Assets 232.7  
Interest rate swap contracts included in Accounts Payable     
Total Liabilities     
Level 1 [Member] | Fair Value Measurements, Recurring [Member] | Forward contracts [Member]
    
Assets    
Forward contracts included in Other Assets     
Level 2 [Member] | Fair Value Measurements, Recurring [Member]
    
Assets    
Cash and cash equivalents     
Restricted cash and cash equivalents     
Restricted short-term investments 0.1  
Total Assets 2.4  
Interest rate swap contracts included in Accounts Payable 0.5  
Total Liabilities 0.5  
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Forward contracts [Member]
    
Assets    
Forward contracts included in Other Assets 2.3  
Level 3 [Member] | Fair Value Measurements, Recurring [Member]
    
Assets    
Cash and cash equivalents     
Restricted cash and cash equivalents     
Restricted short-term investments     
Total Assets     
Interest rate swap contracts included in Accounts Payable     
Total Liabilities     
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Forward contracts [Member]
    
Assets    
Forward contracts included in Other Assets