Long-Term Debt - Additional Information (Detail)

v3.10.0.1

Long-Term Debt - Additional Information (Detail)							1 Months Ended			3 Months Ended	12 Months Ended
	Jan. 01, 2019 USD ($)	Aug. 16, 2018 USD ($)	Apr. 24, 2018	Feb. 15, 2017 USD ($)	Mar. 09, 2016 USD ($)	May 04, 2015	Aug. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) $ / shares	Feb. 28, 2014 USD ($) $ / shares	Mar. 31, 2014 USD ($)	Dec. 31, 2018 USD ($) Day $ / shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2018 USD ($)	Mar. 09, 2011 USD ($)
Debt Instrument [Line Items]
Outstanding principal amount											$ 2,622,900,000
Credit facility, amount repaid											1,231,900,000	$ 483,100,000
Loss on extinguishment of debt											48,500,000
Interest expense											181,000,000	160,800,000	$ 99,300,000
Amortization of deferred financing costs											7,300,000	8,400,000	7,900,000
Stock split conversion ratio			2
Paid-in-capital in excess of par value											341,500,000	407,300,000
Long-term debt											2,453,800,000	2,268,100,000
Convertible notes paid											582,500,000
Letters of credit issued but undrawn											38,200,000
Capped call transactions [Member]
Debt Instrument [Line Items]
Capped call transactions with financial institutions									$ 123,800,000
Prepaid forward share repurchase transactions [Member]
Debt Instrument [Line Items]
Forward share repurchase transactions amount									685,800,000	$ 685,800,000
Convertible Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Outstanding principal amount									1,150,000,000		675,000,000	1,150,000,000
Deferred financing costs										26,600,000
Aggregate principal amount of convertible senior notes issued									1,000,000,000
Interest expense											48,500,000	68,200,000	65,300,000
Non-cash interest expense											29,800,000	41,200,000	38,600,000
Amortization of deferred financing costs											$ 2,900,000	4,000,000	3,800,000
Additional principal amount of convertible notes									$ 150,000,000
Convertible notes, interest rate									2.00%		2.00%
Convertible notes maturity									Aug. 15, 2019		Aug. 15, 2019
Convertible notes, conversion feature											Holders of the 2019 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 2019 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 2019 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 2019 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 2019 Convertible Notes at any time, regardless of the foregoing circumstances.
Convertible notes, number of trading days of threshold limit (whether or not consecutive) | Day											20
Convertible notes, number of trading days of threshold limit in consecutive days | Day											30
Minimum percentage of common share price over conversion price for conversion									130.00%
Principal amount of convertible notes									$ 1,000		$ 1,000
Minimum percentage of the product of common share price and conversion rate for convertible notes									98.00%
Convertible notes conversion rate									23.1816		23.2245
Convertible notes conversion price | $ / shares									$ 43.14		$ 43.06
Stock split conversion ratio									2
Closing price of common shares | $ / shares											$ 58.95
Paid-in-capital in excess of par value									$ 219,100,000	5,100,000
Long-term debt									$ 930,900,000
Effective interest rate on convertible notes									6.20%
Convertible notes paid								$ 583,500,000
Accrued interest								1,000,000
Fair value of liability to convertible notes											$ 662,100,000	1,066,000,000
Unamortized debt discount and debt issuance costs											18,600,000	80,000,000
Convertible senior notes, carrying value of liability component											656,400,000	1,070,000,000
Convertible Senior Notes Due 2019 [Member] | Repurchase of 2019 Convertible Notes [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt								13,100,000
Repurchase of convertible notes								475,000,000
Fair value of liability to convertible notes								459,400,000
Fair value of equity component to convertible notes								123,000,000
Reduction to long-term debt representing liability component of convertible notes								446,400,000
Reduction to additional paid-in capital representing equity component								123,000,000
Convertible Senior Notes Due 2019 [Member] | Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs										$ 21,500,000
Convertible Senior Notes Due 2019 [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Reclassification of difference between aggregate principal amount and carrying value from additional paid in capital to temporary equity	$ 18,600,000
Convertible Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											550,000,000
Deferred financing costs								12,900,000
Aggregate principal amount of convertible senior notes issued								$ 550,000,000
Interest expense											26,600,000
Non-cash interest expense											14,500,000
Amortization of deferred financing costs											$ 1,000,000
Convertible notes, interest rate								2.625%			2.625%
Convertible notes maturity								Mar. 15, 2024			Mar. 15, 2024
Convertible notes, conversion feature											Holders of the 2024 Convertible Notes may convert their notes at their option under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending June 30, 2018, 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 2024 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 2024 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 2024 Convertible Notes for each such day; (iii) if the Company calls the 2024 Convertible Notes for redemption; or (iv) upon the occurrence of specified corporate events. On and after December 15, 2023, holders may convert their 2024 Convertible Notes at any time, regardless of the foregoing circumstances.
Convertible notes, number of trading days of threshold limit (whether or not consecutive) | Day											20
Convertible notes, number of trading days of threshold limit in consecutive days | Day											30
Minimum percentage of common share price over conversion price for conversion								130.00%
Principal amount of convertible notes								$ 1,000			$ 1,000
Minimum percentage of the product of common share price and conversion rate for convertible notes								98.00%
Convertible notes conversion rate								16.0056			16.0352
Convertible notes conversion price | $ / shares								$ 62.48			$ 62.36
Stock split conversion ratio			2
Paid-in-capital in excess of par value								$ 139,900,000
Long-term debt								$ 410,100,000
Effective interest rate on convertible notes								8.40%
Fair value of liability to convertible notes											$ 448,100,000
Unamortized debt discount and debt issuance costs											134,000,000
Convertible senior notes, carrying value of liability component											416,000,000
Deferred financing costs recorded as additional paid-in-capital in excess of par value								$ 3,300,000
Convertible Senior Notes Due 2024 [Member] | Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs								$ 9,600,000
Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											400,000,000
Deferred financing costs											5,200,000			$ 5,400,000
Aggregate principal amount of convertible senior notes issued							$ 400,000,000
Interest expense											11,100,000
Amortization of deferred financing costs											$ 200,000
Convertible notes, interest rate							7.25%				7.25%
Convertible notes maturity							Aug. 15, 2026				Aug. 15, 2026
Senior notes, redemption price, percentage							100.00%
Senior notes, redemption price percentage with equity offerings							107.25%
Carrying amount											$ 394,800,000
Fair value of notes											394,600,000
Senior Notes Due 2026 [Member] | Debt Issuance Costs [Member]
Debt Instrument [Line Items]
Deferred financing costs														$ 5,400,000
Minimum [Member] | Convertible Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											$ 249,100,000
Maximum [Member] | Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Percentage of aggregate pricipal amount of senior notes being redeemed							40.00%
2011 Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, amount repaid												410,000,000	429,700,000
Credit facility, amount borrowed													200,000,000
Interest expense													24,100,000
Amortization of deferred financing costs													$ 4,100,000
2011 Credit Facility [Member] | 2011 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount															$ 700,000,000
Credit facility amendment date											May 04, 2015
Line of credit facility extended maturity period											1 year
Amended maturity date of credit facility											Mar. 09, 2017
Repayment of prior senior secured credit facility				$ 410,000,000
Revolving credit facility termination date											Feb. 15, 2017
2011 Credit Facility [Member] | 2011 Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						4.00%
2011 Credit Facility [Member] | 2011 Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						5.00%
2011 Credit Facility [Member] | 2011 Revolving Credit Facility [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						3.00%
2011 Credit Facility [Member] | 2011 Revolving Credit Facility [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						4.00%
2011 Credit Facility [Member] | 2011 Term Loan [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount															$ 500,000,000
Credit facility amendment date											Jul. 26, 2012
Credit facility, maturity date											Mar. 09, 2016
Repayment of prior senior secured credit facility					$ 229,700,000
2011 Credit Facility [Member] | 2011 Term Loan [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						2.00%
2011 Credit Facility [Member] | 2011 Term Loan [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						3.00%
2011 Credit Facility [Member] | 2011 Term Loan [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						1.00%
2011 Credit Facility [Member] | 2011 Term Loan [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate						2.00%
2017 Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount				1,450,000,000
Credit Facility amended, effective date											Mar. 16, 2018
Deferred financing costs				$ 22,600,000
Credit facility, amount repaid		$ 1,178,100,000									$ 1,226,900,000	$ 73,100,000
Long-term debt, weighted average interest rate												6.79%
Credit facility, amount borrowed												$ 1,300,000,000
Borrowings under the senior secured credit facility												1,226,900,000
Foreign currency borrowings, outstanding												0
2017 Credit Facility [Member] | Other Expense (Income), Net [Member]
Debt Instrument [Line Items]
Loss on extinguishment of debt											$ 35,400,000
2017 Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				1.00%
2017 Credit Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Base rate interest rate floor				1.75%
2017 Credit Facility [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				0.50%
2017 Credit Facility [Member] | 2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount				$ 150,000,000
Credit facility, maturity date											Feb. 15, 2022
Repayment of prior senior secured credit facility		1,178,100,000
Credit facility LIBOR minimum floor rate interest				0.75%
Borrowings under the senior secured credit facility												0
2017 Credit Facility [Member] | 2017 Revolving Credit Facility [Member] | Base Rate [Member] | Scenario Leverage Ratio One [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				3.50%
2017 Credit Facility [Member] | 2017 Revolving Credit Facility [Member] | Base Rate [Member] | Scenario Leverage Ratio Two [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				3.75%
2017 Credit Facility [Member] | 2017 Revolving Credit Facility [Member] | Eurodollar [Member] | Scenario Leverage Ratio One [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				4.50%
2017 Credit Facility [Member] | 2017 Revolving Credit Facility [Member] | Eurodollar [Member] | Scenario Leverage Ratio Two [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				4.75%
2017 Credit Facility [Member] | 2017 Term Loan B [Member]
Debt Instrument [Line Items]
Credit facility, maturity date											Feb. 15, 2023
Outstanding principal amount				$ 1,300,000,000
Senior secured credit facility, discount percentage				2.00%
Senior secured credit facility, discount amount				$ 26,000,000
Borrowings under the senior secured credit facility												1,226,900,000
2017 Credit Facility [Member] | 2017 Term Loan B [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Outstanding principal amount												1,190,200,000
Debt instrument, fair value												1,226,100,000
2017 Credit Facility [Member] | 2017 Term Loan B [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				4.50%
2017 Credit Facility [Member] | 2017 Term Loan B [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate				5.50%
2017 Credit Facility [Member] | 2017 Term Loan B [Member] | 2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit facility termination date											Aug. 16, 2018
2018 Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount		1,250,000,000
Deferred financing costs		11,700,000
Credit facility, amount repaid											$ 5,000,000
Line of credit facility, frequency of interest payments											quarterly
Long-term debt, weighted average interest rate											6.80%
Credit facility, amount borrowed											$ 1,000,000,000
Borrowings under the senior secured credit facility											995,000,000
Foreign currency borrowings, outstanding											0
2018 Credit Facility [Member] | Minimum [Member] | 2019 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Outstanding principal amount		350,000,000
2018 Credit Facility [Member] | Minimum [Member] | 2024 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Outstanding principal amount		$ 350,000,000
2018 Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		1.00%
2018 Credit Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Base rate interest rate floor		1.00%
2018 Credit Facility [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		0.50%
2018 Credit Facility [Member] | 2018 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum amount		$ 250,000,000
Credit facility, maturity date		Aug. 16, 2023
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.50%
Borrowings under the senior secured credit facility											$ 0
2018 Credit Facility [Member] | 2018 Revolving Credit Facility [Member] | 2019 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Feb. 14, 2019
2018 Credit Facility [Member] | 2018 Revolving Credit Facility [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		2.00%
2018 Credit Facility [Member] | 2018 Revolving Credit Facility [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		2.00%
2018 Credit Facility [Member] | 2018 Term Loan A [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Aug. 16, 2023
Outstanding principal amount		$ 250,000,000
Voluntary prepayment premium percentage											1.00%
Borrowings under the senior secured credit facility											$ 246,900,000
2018 Credit Facility [Member] | 2018 Term Loan A [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											245,400,000
Debt instrument, fair value											$ 240,700,000
2018 Credit Facility [Member] | 2018 Term Loan A [Member] | 2019 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Feb. 14, 2019
2018 Credit Facility [Member] | 2018 Term Loan A [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		3.00%
2018 Credit Facility [Member] | 2018 Term Loan A [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		3.00%
2018 Credit Facility [Member] | 2018 Term Loan B [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Aug. 18, 2025
Outstanding principal amount		$ 750,000,000
Senior secured credit facility, discount percentage		0.25%
Senior secured credit facility, discount amount		$ 1,900,000
Voluntary prepayment premium percentage											1.00%
Borrowings under the senior secured credit facility											$ 748,100,000
2018 Credit Facility [Member] | 2018 Term Loan B [Member] | Level 2 [Member]
Debt Instrument [Line Items]
Outstanding principal amount											738,200,000
Debt instrument, fair value											729,300,000
2018 Credit Facility [Member] | 2018 Term Loan B [Member] | 2019 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		May 16, 2019
2018 Credit Facility [Member] | 2018 Term Loan B [Member] | 2024 Convertible Notes Exceeds 350 Million [Member]
Debt Instrument [Line Items]
Credit facility, maturity date		Dec. 15, 2023
2018 Credit Facility [Member] | 2018 Term Loan B [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		2.25%
2018 Credit Facility [Member] | 2018 Term Loan B [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Interest rate spread on variable rate		3.25%
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount of convertible senior notes issued		$ 400,000,000
2018 and 2017 Credit Facility [Member]
Debt Instrument [Line Items]
Interest expense											83,600,000
Non-cash interest expense											2,900,000
Amortization of deferred financing costs											$ 3,200,000
2017 and 2011 Credit Facility [Member]
Debt Instrument [Line Items]
Interest expense												87,000,000
Non-cash interest expense												4,200,000
Amortization of deferred financing costs												$ 4,400,000