Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 29, 2020	Jun. 28, 2020	Dec. 29, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Leases, remaining lease term (years)	15 years
Operating lease right-of-use assets		$ 85.8	$ 60.4
Operating lease current liabilities		19.5	20.1
Operating lease noncurrent liabilities		69.9	$ 43.3
Operating lease, weighted average discount rate	4.80%
2020, remaining		1.6
2021		3.3
2022		3.3
2023		3.4
2024		3.4
2025		3.4
Thereafter		$ 34.0
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets				$ 74.1
Operating lease current liabilities				19.8
Operating lease noncurrent liabilities				$ 54.3
Minimum
Lessee, Lease, Description [Line Items]
Leases, remaining lease term (years)		1 year
Maximum
Lessee, Lease, Description [Line Items]
Leases, remaining lease term (years)		15 years
Sale of Main Headquarters
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 37.6
Operating lease current liabilities	1.2
Operating lease noncurrent liabilities	$ 36.1