Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Additional Information (Detail)

v2.4.0.8
Long-Term Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended 1 Months Ended 3 Months Ended 9 Months Ended 9 Months Ended 9 Months Ended 1 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Mar. 31, 2011
Credit Facility [Member]
Sep. 30, 2013
Credit Facility [Member]
Jun. 30, 2013
Credit Facility [Member]
Mar. 31, 2013
Credit Facility [Member]
Sep. 30, 2013
Credit Facility [Member]
Dec. 31, 2012
Credit Facility [Member]
Sep. 30, 2013
Credit Facility [Member]
Maximum [Member]
Sep. 30, 2013
Credit Facility [Member]
Minimum [Member]
Sep. 30, 2013
Credit Facility [Member]
Senior secured revolving credit facility [Member]
Dec. 31, 2012
Credit Facility [Member]
Senior secured revolving credit facility [Member]
Mar. 09, 2011
Credit Facility [Member]
Senior secured revolving credit facility [Member]
Sep. 30, 2013
Credit Facility [Member]
Senior secured revolving credit facility [Member]
Maximum [Member]
Sep. 30, 2013
Credit Facility [Member]
Senior secured revolving credit facility [Member]
Minimum [Member]
Jul. 31, 2012
Credit Facility [Member]
Term Loan [Member]
Sep. 30, 2013
Credit Facility [Member]
Term Loan [Member]
Dec. 31, 2012
Credit Facility [Member]
Term Loan [Member]
Jul. 26, 2012
Credit Facility [Member]
Term Loan [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option One [Member]
Senior secured revolving credit facility [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option One [Member]
Senior secured revolving credit facility [Member]
Maximum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option One [Member]
Senior secured revolving credit facility [Member]
Minimum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option One [Member]
Term Loan [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option One [Member]
Term Loan [Member]
Maximum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option One [Member]
Term Loan [Member]
Minimum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option Two [Member]
Senior secured revolving credit facility [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option Two [Member]
Senior secured revolving credit facility [Member]
Maximum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option Two [Member]
Senior secured revolving credit facility [Member]
Minimum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option Two [Member]
Term Loan [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option Two [Member]
Term Loan [Member]
Maximum [Member]
Sep. 30, 2013
Credit Facility [Member]
Interest Rate Option Two [Member]
Term Loan [Member]
Minimum [Member]
Debt Instrument [Line Items]                                                                    
Credit facility, maximum amount                               $ 700.0           $ 500.0                        
Credit facility, maturity period                   5 years                                                
Credit facility, expiration date                   Mar. 09, 2016                                                
Interest rate spread on variable rate                       2.50% 1.50%                     2.50% 1.50%   2.50% 1.50%   1.50% 0.50%   1.50% 0.50%
Variable rate basis                   LIBOR                         LIBOR     LIBOR     The base rate under the Credit Facility represents the highest of the Federal Funds Rate plus 0.50%, one-month LIBOR plus 1.00%, and the prime rate offered by Bank of America.     Base rate    
Base rate in excess of Federal Funds Rate                                                         0.50%          
Base rate in excess of one-month LIBOR                                                         1.00%          
Credit facility, unused capacity, commitment fee percentage                                 0.50% 0.25%                                
Repayment of all amounts outstanding under the Prior Credit Facility by using borrowings under the new Credit Facility           196.0                         500.0                              
Deferred financing costs           5.7                         4.5                              
Long-term debt, weighted average interest rate             2.18%     2.18% 1.96%                                              
Credit facility, amount borrowed             250.0   513.0                                                  
Credit facility, amount repaid             262.5 12.5 25.5                                                  
Credit facility, amount outstanding 950.0   950.0   487.5   950.0     950.0 487.5     500.0 0         450.0 487.5                          
Foreign currency borrowings outstanding             0     0 0                                              
Aggregate annual maturities, 2013             18.8     18.8                                                
Aggregate annual maturities, 2014             81.2     81.2                                                
Aggregate annual maturities, 2015             100.0     100.0                                                
Aggregate annual maturities, 2016             750.0     750.0                                                
Interest expense $ 6.7 $ 5.0 $ 21.1 $ 12.4