Fair Value Measurements - (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Oct. 02, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, excluding convertible senior notes due 2025	$ 1,349.4	$ 1,321.0
Convertible senior notes due 2025	406.1	0.0
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, excluding convertible senior notes due 2025	1,349.4	1,321.0
Convertible senior notes due 2025	717.2	0.0
Cross-currency swap derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities:	29.9	8.9
Cross-currency swap derivative contracts | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities:	29.9	8.9
Cross-currency swap derivative contracts | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities:	29.9	8.9
Interest rate swap derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:		0.1
Derivative liabilities:	9.7
Interest rate swap derivative contracts | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0.0	0.1
Derivative liabilities:	9.7	0.0
Interest rate swap derivative contracts | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:	0.0	0.1
Derivative liabilities:	$ 9.7	$ 0.0