Business and Summary of Significant Accounting Policies Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016
Other Current Liabilities [Member]
Property and equipment [Line Items]
Deferred Rent Credit, Current	$ 1.0	$ 0.2
Deferred Lease Incentives, Current	3.0	3.0
Other Noncurrent Liabilities [Member]
Property and equipment [Line Items]
Deferred Rent Credit, Noncurrent	10.0	10.0
Deferred Lease Incentives, Noncurrent	$ 10.0	$ 9.0
Minimum [Member]
Property and equipment [Line Items]
Lessee, Operating Lease, Term of Contract	5 years
Maximum [Member]
Property and equipment [Line Items]
Lessee, Operating Lease, Term of Contract	10 years