Significant Customers (Details) - U.S. Government - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2021	Sep. 27, 2020	Sep. 26, 2021	Sep. 27, 2020
Revenue, Major Customer [Line Items]
Sales to the U.S. Government, amount	$ 143.7	$ 145.3	$ 432.1	$ 398.8
Government contracts | Revenue
Revenue, Major Customer [Line Items]
Sales to the U.S. Government, percentage of total revenue (percent)	72.00%	72.00%	72.00%	74.00%