Severance, Restructuring, and Acquisition Integration Activities Severance, Restructuring and Acquisition Integration Activities - Accrued Severance (Details) - Employee Severance - Enterprise Solutions - Grass Valley And SAM Integration Program - USD ($) $ in Thousands	3 Months Ended
	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Restructuring Reserve	$ 3,560	$ 406	$ 0
Restructuring Reserve, Period Increase (Decrease)	10,714	456
Payments for Restructuring	(7,556)	$ 50
Restructuring Reserve, Translation and Other Adjustment	$ (4)