Debt And Credit Facilities - Narrative (Details) $ / shares in Units, shares in Millions					12 Months Ended
	Feb. 09, 2021 USD ($)	May 21, 2020 USD ($) tradingDay $ / shares shares	May 06, 2020 USD ($)	Sep. 20, 2019 USD ($)	Dec. 31, 2020 USD ($) tradingDay $ / shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 EUR (€)	Sep. 20, 2019 EUR (€)
Debt Instrument [Line Items]
Unamortized debt issuance costs and discount					$ 109,600,000	$ 2,200,000
Total borrowings under term loan				$ 1,300,000,000
Senior unsecured revolving credit facility				$ 250,000,000.0
Rate in excess of Federal funds rate					0.0050			0.0050
Rate in excess of Eurocurrency rate					0.010			0.010
Leverage ratio					3.75			3.75
Contingency provision on the ratio of indebtedness to net capital					4.25			4.25
Contingency provision, purchase price in excess of $100 million					$ 100,000,000.0
Interest coverage ratio (at least)					3.00			3.00
Payments of debt restructuring costs			$ 2,800,000
Deferred finance costs, debt restructuring			$ 2,300,000
Proceeds from issuance of convertible senior notes					$ 517,500,000	0	$ 0
Conversion price (in USD per share) | $ / shares					$ 21.01
Total debt					$ 1,794,500,000	$ 1,324,900,000
US term loan due 2022
Debt Instrument [Line Items]
Debt instrument, term				3 years
Term loan				$ 650,000,000.0
Loan facility interest rates					4.25%	3.53%
Total debt				$ 650,000,000.0	$ 648,100,000	$ 648,700,000
Debt issuance costs					$ 1,900,000	$ 1,300,000
Euro term loan due 2022
Debt Instrument [Line Items]
Debt instrument, term				3 years
Term loan				$ 600,000,000.0				€ 600,000,000.0	€ 600,000,000.0
Loan facility interest rates					3.33%	1.20%
Total debt					$ 731,600,000	$ 672,000,000.0
Debt issuance costs					1,300,000	900,000
Euro term loan due 2022 | Subsequent Event
Debt Instrument [Line Items]
Repayments of short-term debt	$ 472,000,000.0
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity					250,000,000.0
Revolving credit facility increase					200,000,000.0
Line of credit facility, outstanding borrowings					0	0
Revolving Credit Facility | Standby letters of credit
Debt Instrument [Line Items]
Revolving credit facility maximum borrowing capacity					$ 20,000,000.0
Minimum
Debt Instrument [Line Items]
Facility fee					0.09%
Maximum
Debt Instrument [Line Items]
Facility fee					0.225%
LIBOR | Minimum | Credit facility
Debt Instrument [Line Items]
Margin spread of variable interest rate					0.785%
LIBOR | Maximum | Credit facility
Debt Instrument [Line Items]
Margin spread of variable interest rate					1.625%
Base Rate | Minimum
Debt Instrument [Line Items]
Margin spread of variable interest rate					0.00%
Base Rate | Maximum
Debt Instrument [Line Items]
Margin spread of variable interest rate					0.625%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, term				5 years
Convertible Debt | 2.375% convertible senior notes over allotment option
Debt Instrument [Line Items]
Term loan		$ 67,500,000
Convertible Debt | 2.375% convertible senior notes
Debt Instrument [Line Items]
Term loan		517,500,000
Proceeds from issuance of convertible senior notes		$ 502,600,000
Interest rate		2.375%
Conversion price (in USD per share) | $ / shares		$ 21.01			$ 23.79
Redemption price		100.00%
Threshold percentage of stock price trigger		130.00%			130.00%
Convertible debt, trading days (in trading days) | tradingDay		20			20
Convertible debt, consecutive trading days (in trading days) | tradingDay		30			30
Total debt		$ 410,900,000			$ 411,100,000	$ 0
Convertible debt, carrying amount of equity component		106,600,000
Debt issuance costs		11,900,000			$ 10,800,000
Gross debt issuance costs, equity component		3,100,000
Deferred tax liabilities, financing arrangements		$ 20,500,000
Effective interest rate					7.30%			7.30%
Convertible debt, fair value					$ 902,700,000
If-converted value in excess of principal					$ 313,100,000
Convertible debt, conversion ratio		0.0475862
Convertible Debt | 2.375% convertible senior notes, capped calls
Debt Instrument [Line Items]
Conversion price (in USD per share) | $ / shares		$ 23.79
Convertible debt, stock price trigger (in USD per share) | $ / shares		$ 21.01
Convertible debt, capped calls (in shares) | shares		2.9
Convertible debt expense, capped calls		$ 20,700,000