Other (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 24, 2017	Sep. 30, 2018	Sep. 24, 2017	Dec. 31, 2017
Other Expense [Line Items]
Advertising expense	$ 40.4	$ 26.6	$ 107.6	$ 86.0
Severance liability	8.3		8.3		$ 18.8
Selling, General and Administrative Expenses
Other Expense [Line Items]
Severance costs				23.0
Capitalized Computer Software Costs
Other Expense [Line Items]
Capitalized computer software amortization	4.1	4.0	11.4	9.7
Headquarters Redesign and Consolidation
Other Expense [Line Items]
Costs incurred during the period		2.5	3.1	6.9
Restructuring costs capitalized in period	3.0	26.0	14.0	$ 37.0
Severance | Selling, General and Administrative Expenses
Other Expense [Line Items]
Severance costs	$ 0.3	$ 2.1	$ 4.9