Leases - Effects of New Accounting Pronouncement (Details) - USD ($) $ in Millions	Dec. 28, 2019	Dec. 30, 2018	Dec. 29, 2018
Assets
Property and equipment - net	$ 7.7	$ 7.8	$ 7.8
Operating lease right-of-use assets	55.6	60.5
Current:
Other accrued liabilities	2.8	1.2	1.2
Operating lease liability	19.5	20.2
Non-current:
Other long-term liabilities	10.0	6.6	$ 6.6
Operating lease liabilities	$ 37.5	40.4
Accounting Standards Update 2016-02 [Member]
Assets
Property and equipment - net		0.0
Operating lease right-of-use assets		60.5
Current:
Other accrued liabilities		0.0
Operating lease liability		20.2
Non-current:
Other long-term liabilities		0.0
Operating lease liabilities		$ 40.4