Discontinued Operations (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consolidated income from continuing operations before taxes	$ 3,573,000	$ 45,351,000	$ 20,656,000	$ 79,456,000
Grass Valley | Discontinued Operations, Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Impairment Charges	89,810,000	0	113,007,000	0
Capital Expenditure, Discontinued Operations	8,500,000	8,700,000	16,400,000	14,500,000
Share-based Compensation, Discontinued Operations	0.0	$ 300,000	900,000	$ 600,000
Accumulated Other Comprehensive Income (Loss), net of tax, Discontinued Operations	$ 11.5		$ 11.5		$ 42.3