Acquisition - Consideration Paid (Details) - USD ($) $ in Millions				12 Months Ended
	Jun. 30, 2020	Jun. 15, 2020	Feb. 27, 2019	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Business Acquisition [Line Items]
Total consideration				$ 51.5	$ 17.7	$ 2.9
FTT Inc
Business Acquisition [Line Items]
Cash paid			$ 20.7
Deferred purchase consideration			15.3
Common stock issued			27.0
Consideration transferred, gross			63.0
Less: Cash acquired			(3.0)
Total consideration			$ 60.0
CPI ASC Signal Division, Inc.
Business Acquisition [Line Items]
Cash paid	$ 34.9	$ 35.0
Less: Cash acquired	(2.0)
Total consideration	$ 32.9