Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities - Additional Information (Detail)

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Derivative Instruments and Hedging Activities - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 1 Months Ended 9 Months Ended 12 Months Ended
Aug. 31, 2009
Agreement
Sep. 30, 2012
Dec. 31, 2009
Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]        
Maximum duration of hedging of interest rate swap derivative exposure   10 months    
Number of interest rate swap agreements 4      
Interest rate swap agreements, Aggregate Notional Amounts     $ 140.0  
Average effective fixed rate on notional balances of debt and interest rate swap, minimum     4.28%  
Average effective fixed rate on notional balances of debt and interest rate swap, maximum     5.28%  
Outstanding notional amount of foreign currency forward contract   424.6    
Average remaining maturity of foreign currency derivative   Less than eight months   Less than fifteen months
Interest Rate Swap
        
Derivative Instruments, Gain (Loss) [Line Items]        
Weighted average fixed interest rate on notional amounts     2.78%  
Interest rate applicable on interest rate swap agreements for stipulated period     1 Month LIBOR rate  
Expiration date of interest rate swap agreements     Jul. 01, 2013  
Effective date of interest rate swap agreements     Dec. 31, 2009  
Liabilities related to Interest rate swaps at fair value   3.0   5.1
Foreign exchange currency contracts
        
Derivative Instruments, Gain (Loss) [Line Items]        
Outstanding notional amount of foreign currency forward contract   131.6   64.4
Expected Maturity Period of Foreign Currency Forward Contracts   8 months    
Fair Value of outstanding foreign currency forward contracts   0.9   4.4
Derivative liability Fair Value   $ 3.6    
Freestanding Derivatives
        
Derivative Instruments, Gain (Loss) [Line Items]        
Average remaining maturity of foreign currency derivative   Within 1 month   Within 1 month
Minimum
        
Derivative Instruments, Gain (Loss) [Line Items]        
Interest on new credit facility   LIBOR + 1.50%    
Maximum
        
Derivative Instruments, Gain (Loss) [Line Items]        
Interest on new credit facility   LIBOR + 2.50%