Significant Customers (Details) - U.S. Government - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Revenue, Major Customer [Line Items]
Sales to the U.S. Government, amount	$ 145.3	$ 126.2	$ 398.8	$ 377.0
Government contracts | Revenue
Revenue, Major Customer [Line Items]
Sales to the U.S. Government, percentage of total revenue (percent)	72.00%	69.00%	74.00%	71.00%