Severance, Restructuring, and Acquisition Integration Activities Severance, Restructuring, and Acquisition Integration Activities - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended			31 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2017	Oct. 01, 2017	Jul. 02, 2017	Apr. 02, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs	$ 11,600	$ 11,700	$ 24,900	$ 20,400	$ 9,900	$ 16,700	$ 9,600	$ 6,600	$ 68,613	$ 42,790	$ 31,140
Cost of Sales
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs									28,100	32,600	12,300
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs									35,000	10,000	18,000
Research and Development
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs									$ 5,500	200	800
Maximum
Restructuring Cost and Reserve [Line Items]
Restructuring and integration cost payable period									60 days
Grass Valley And SAM Integration Program
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs									$ 42,300
Industrial Manufacturing Footprint Program
Restructuring Cost and Reserve [Line Items]
Severance, restructuring, and acquisition integration costs									$ 17,700	$ 30,600	$ 17,800	$ 66,100
Scenario, Forecast \| Grass Valley And SAM Integration Program
Restructuring Cost and Reserve [Line Items]
Expected restructuring cost remaining													$ 3,000