Earnings Per Share - Components of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Oct. 02, 2020	Jul. 03, 2020	Apr. 03, 2020	Dec. 31, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income	$ 108.4	$ 35.6	$ (93.5)	$ (17.2)	$ 56.1	$ 62.1	$ 61.5	$ 37.9	$ 33.3	$ 217.6	$ 230.7
Denominator:
Weighted-average common shares outstanding used in basic EPS (in shares)									159.6	136.2	127.9
Assumed exercise of dilutive options and vesting of dilutive restricted stock units (in shares)									2.2	0.2	0.0
Assumed conversion of the Notes (in shares)									2.3	0.0	0.0
Weighted average common shares outstanding used in diluted EPS (in shares)									164.1	136.4	127.9
Earnings per share:
Basic (in USD per share)	$ 0.68	$ 0.22	$ (0.59)	$ (0.11)	$ 0.35	$ 0.48	$ 0.48	$ 0.30	$ 0.21	$ 1.60	$ 1.80
Diluted (in USD per share)	$ 0.64	$ 0.22	$ (0.59)	$ (0.11)	$ 0.35	$ 0.48	$ 0.48	$ 0.30	$ 0.20	$ 1.60	$ 1.80