Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Additional Information (Detail)

v3.3.1.900
Long-Term Debt - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 12 Months Ended
Sep. 30, 2015
May. 04, 2015
Feb. 28, 2014
Jul. 31, 2012
Mar. 31, 2011
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Jul. 26, 2012
Mar. 09, 2011
Debt Instrument [Line Items]                      
Issuance costs   $ 6,200,000                  
Allowable annual dividend payment or repurchase of common stock under credit facility             $ 233,000,000        
Credit facility terms description             The Credit Facility restricts the Company’s ability to pay dividends or repurchase its common shares to a maximum of $233.0 million until maturity and for every one dollar of share repurchase or dividend paid, the revolving credit facility’s borrowing capacity is permanently decreased by two dollars.        
Borrowings under the senior secured credit facility             $ 639,500,000 $ 848,300,000      
Paid-in capital in excess of par value             438,200,000 409,100,000      
Proceeds received from the issuance of the Convertible notes               1,150,000,000      
Long-term debt             1,622,000,000 1,791,800,000      
Convertible senior notes, carrying value of liability component             982,500,000 943,500,000      
Interest expense             100,500,000 91,700,000 $ 26,600,000    
Amortization of deferred financing costs             8,500,000 6,800,000 2,600,000    
Letters of credit issued but undrawn             45,300,000        
Prepaid forward share repurchase transactions [Member]                      
Debt Instrument [Line Items]                      
Paid-in capital in excess of par value           $ 31,900,000          
Forward share repurchase transactions amount     $ 685,800,000     685,800,000   1,267,100,000      
Capped call transactions [Member]                      
Debt Instrument [Line Items]                      
Capped call transactions with financial institutions     123,800,000                
Convertible Senior Notes [Member]                      
Debt Instrument [Line Items]                      
Deferred financing costs           21,500,000          
Total principal amount of convertible notes             1,150,000,000 1,150,000,000      
Issuance costs           26,600,000          
Paid-in capital in excess of par value     219,100,000                
Proceeds received from the issuance of the Convertible notes     1,150,000,000                
Long-term debt     $ 930,900,000                
Effective interest rate on convertible notes     6.20%                
Unamortized debt discount and debt issuance costs             167,600,000 206,500,000      
Convertible senior notes, carrying value of liability component             982,500,000 943,500,000      
Fair value of liability to convertible notes             795,900,000 $ 802,800,000      
Interest expense             61,700,000        
Non-cash interest expense             35,700,000        
Amortization of deferred financing costs             $ 3,200,000        
Convertible Senior Notes [Member] | Debt Issuance Costs [Member]                      
Debt Instrument [Line Items]                      
Paid-in capital in excess of par value           $ 5,100,000          
Convertible Debt [Member]                      
Debt Instrument [Line Items]                      
Total principal amount of convertible notes     $ 1,150,000,000                
Debt maturity date     Aug. 15, 2019                
Aggregate principal amount of convertible senior notes issued     $ 1,000,000,000                
Additional principal amount of convertible notes     $ 150,000,000                
Convertible notes, interest rate     2.00%                
Convertible notes, conversion feature             Holders of the Convertible Notes may convert their notes at their option under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending March 31, 2014, if the last reported sale price of the Company’s common shares for at least 20 trading days (whether or not consecutive) in a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 130% of the conversion price for the Convertible Notes on each applicable trading day; (ii) during the five business-day period immediately after any five consecutive trading day period, or the measurement period, in which the trading price per $1,000 principal amount of Convertible Notes for each trading day of that measurement period was less than 98% of the product of the last reported sale price of the Company’s common shares and the conversion rate for the Convertible Notes for each such day; or (iii) upon the occurrence of specified corporate events. On and after May 15, 2019, holders may convert their Convertible Notes at any time, regardless of the foregoing circumstances.        
Convertible notes, number of trading days of threshold limit (whether or not consecutive)             20 days        
Convertible notes, number of trading days of threshold limit in consecutive days             30 days        
Minimum percentage of common share price over conversion price for conversion     130.00%                
Principal amount of convertible notes     $ 1,000                
Minimum percentage of the product of common share price and conversion rate for convertible notes     98.00%                
Convertible notes initial conversion rate     11.5908                
Convertible notes initial conversion price             $ 86.28 $ 86.28      
Convertible Debt [Member] | Capped call transactions [Member]                      
Debt Instrument [Line Items]                      
Convertible notes initial conversion price     $ 86.28                
Senior secured revolving credit facility [Member]                      
Debt Instrument [Line Items]                      
Amount required to maintain on consolidated cash and cash equivalents             $ 200,000,000        
Senior Secured Credit Facility [Member]                      
Debt Instrument [Line Items]                      
Credit facility borrowings used to repay outstanding borrowings         $ 196,000,000            
Deferred financing costs         $ 5,700,000            
Credit facility amendment date             May 04, 2015        
Credit facility interest rate description             Until March 9, 2016, the applicable interest rates on the Company’s borrowings under the Credit Facility will increase by 2.00% such that borrowings under the Credit Facility will bear interest at either LIBOR plus the applicable margin between 4.00% and 5.00% or the base rate plus the applicable margin between 3.00% and 4.00%.        
Long-term debt, weighted average interest rate             2.78% 3.04%      
Credit facility, amount borrowed             $ 0 $ 50,000,000 763,000,000    
Credit facility, amount repaid             210,300,000 131,300,000 $ 319,200,000    
Borrowings under the senior secured credit facility             639,700,000 850,000,000      
Foreign currency borrowings, outstanding             0 0      
Aggregate annual maturities of credit facility, 2016             229,700,000        
Aggregate annual maturities of credit facility, 2017             410,000,000        
Aggregate annual maturities of credit facility, 2019             $ 1,150,000,000        
Senior Secured Credit Facility [Member] | Minimum [Member]                      
Debt Instrument [Line Items]                      
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage             0.40%        
Senior Secured Credit Facility [Member] | Maximum [Member]                      
Debt Instrument [Line Items]                      
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage             0.50%        
Senior Secured Credit Facility [Member] | Base Rate [Member]                      
Debt Instrument [Line Items]                      
Variable rate basis             Facility will bear interest at either LIBOR plus the applicable margin between 4.00% and 5.00% or the base rate plus the applicable margin between 3.00% and 4.00%.        
Senior Secured Credit Facility [Member] | Until March 9, 2016 [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate increase by percentage   0.50%                  
Senior Secured Credit Facility [Member] | After March 9, 2016 [Member]                      
Debt Instrument [Line Items]                      
Interest rate increased by percentage   2.00%                  
Senior Secured Credit Facility [Member] | After March 9, 2016 [Member] | LIBOR [Member] | Minimum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   4.00%                  
Senior Secured Credit Facility [Member] | After March 9, 2016 [Member] | LIBOR [Member] | Maximum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   5.00%                  
Senior Secured Credit Facility [Member] | After March 9, 2016 [Member] | Base Rate [Member] | Minimum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   3.00%                  
Senior Secured Credit Facility [Member] | After March 9, 2016 [Member] | Base Rate [Member] | Maximum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   4.00%                  
Senior Secured Credit Facility [Member] | Term Loan [Member]                      
Debt Instrument [Line Items]                      
Credit facility, maximum amount                   $ 500,000,000  
Credit facility borrowings used to repay outstanding borrowings       $ 500,000,000              
Deferred financing costs       $ 4,500,000              
Debt maturity date   Mar. 09, 2016                  
Borrowings under the senior secured credit facility             $ 229,700,000 350,000,000      
Senior Secured Credit Facility [Member] | Convertible Senior Notes [Member]                      
Debt Instrument [Line Items]                      
Total principal amount of convertible notes     $ 1,150,000,000                
Senior Secured Credit Facility [Member] | Convertible Debt [Member]                      
Debt Instrument [Line Items]                      
Deferred financing costs     $ 2,300,000                
Applicable margin payable, percentage     0.50%                
Consolidated leverage ratio             2.50 to 1.00        
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member]                      
Debt Instrument [Line Items]                      
Credit facility, maximum amount             $ 425,000,000       $ 700,000,000
Line of credit facility extended maturity period             1 year        
Amended maturity date of credit facility   Mar. 09, 2017                  
Decreased amount in credit facility borrowing capacity $ (39,100,000) $ (235,900,000)                  
Variable rate basis             Credit Facility now bear interest at either LIBOR plus the applicable margin between 2.00% and 3.00% or the base rate plus the applicable margin between 1.00% and 2.00%.        
Borrowings under the senior secured credit facility             $ 410,000,000 $ 500,000,000      
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member] | Minimum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   2.00%                  
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member] | Maximum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   3.00%                  
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member] | LIBOR [Member]                      
Debt Instrument [Line Items]                      
Credit facility LIBOR minimum floor rate interest   0.25%                  
Variable rate basis             LIBOR        
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member] | Base Rate [Member]                      
Debt Instrument [Line Items]                      
Variable rate basis             The base rate under the Credit Facility represents the highest of the Federal Funds Rate plus 0.50%, the one-month LIBOR plus 1.00%, and the prime rate offered by Bank of America.        
Base rate in excess of Federal Funds Rate             0.50%        
Base rate in excess of one-month LIBOR             1.00%        
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member] | Base Rate [Member] | Minimum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   1.00%                  
Senior Secured Credit Facility [Member] | Senior secured revolving credit facility [Member] | Base Rate [Member] | Maximum [Member]                      
Debt Instrument [Line Items]                      
Interest rate spread on variable rate   2.00%