Segment and Geographic Information - Reconciliation of Net Loss to Adjusted EBITDA (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Segment Reporting Information [Line Items]
Net loss	$ 14.7	$ (28.5)	$ (44.4)	$ (171.0)
Interest expense, net	36.1	48.9	112.5	148.6
Provision for (benefit from) income taxes	6.0	(10.3)	24.4	(2.4)
Depreciation and amortization	80.8	79.9	246.6	239.6
Stock-based compensation			19.6	6.2
Restructuring and severance-related costs	1.7	4.7	4.7	9.3
Arbitration award	(7.4)	0.0	(7.4)	0.0
Tax indemnification (income) expense, net	(0.2)	16.5	(0.6)	11.6
Loss on extinguishment of debt	0.0	0.0	50.3	12.6
Quotient upfront payment	0.0	7.5	0.0	7.5
Unrealized foreign currency exchange (gains) losses, net	0.0	6.3	0.0	(46.0)
Other adjustments	2.9	4.7	14.5	14.4
Adjusted EBITDA	139.6	119.5	420.1	322.4
2014 Plan [Member]
Segment Reporting Information [Line Items]
Stock-based compensation	$ 5.0	$ 2.4	$ 19.5	$ 6.2