Debt And Credit Facilities - Narrative (Details) $ / shares in Units, shares in Millions					9 Months Ended		12 Months Ended
	Jun. 15, 2021 USD ($)	Feb. 09, 2021 USD ($)	May 21, 2020 USD ($) tradingDay $ / shares shares	Sep. 20, 2019 USD ($)	Oct. 01, 2021 USD ($) tradingDay $ / shares	Oct. 02, 2020 USD ($)	Dec. 31, 2020 USD ($) tradingDay $ / shares	Oct. 01, 2021 EUR (€)	Dec. 31, 2020 EUR (€)	Sep. 20, 2019 EUR (€)
Debt Instrument [Line Items]
Unamortized debt issuance costs and discount					$ 94,200,000		$ 109,600,000
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
Proceeds from issuance of convertible senior notes					$ 0	$ 517,500,000
Conversion price (in USD per share) | $ / shares					$ 21.01		$ 21.01
Total debt					$ 1,314,500,000		$ 1,794,500,000
US term loan due 2024
Debt Instrument [Line Items]
Debt instrument, term				3 years
Term loan				$ 650,000,000.0
Loan facility interest rates					1.25%		4.25%
Total debt				$ 650,000,000.0	$ 647,100,000		$ 648,100,000
Debt issuance costs					$ 2,900,000		$ 1,900,000
Euro term loan due 2024
Debt Instrument [Line Items]
Debt instrument, term				3 years
Term loan | €								€ 208,000,000.0	€ 600,000,000.0	€ 600,000,000.0
Repayment of debt		$ 472,000,000.0
Loan facility interest rates					0.95%		3.33%
Total debt					$ 240,700,000		$ 731,600,000
Debt issuance costs					500,000		1,300,000
Revolving Credit Facility
Debt Instrument [Line Items]
Senior unsecured revolving credit facility	$ 750,000,000.0			$ 250,000,000.0
Increase limit of revolving credit facility	350,000,000.0
Cash and cash equivalent threshold	$ 250,000,000.0
EBITDA threshold	0.50
Payments of debt restructuring costs	$ 2,100,000
Revolving credit facility maximum borrowing capacity					750,000,000.0
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
Redemption price			100.00%
Threshold percentage of stock price trigger			130.00%		130.00%		130.00%
Convertible debt, trading days (in trading days) | tradingDay			20		20		20
Convertible debt, consecutive trading days (in trading days) | tradingDay			30		30		30
Total debt			$ 410,900,000		$ 426,700,000		$ 411,100,000
Convertible debt, carrying amount of equity component			106,600,000
Debt issuance costs			11,900,000		$ 9,400,000		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%
If-converted value in excess of principal					$ 536,000,000.0		$ 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