Discontinued Operations (Details) - USD ($)		3 Months Ended		9 Months Ended
	Jul. 02, 2020	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from disposal of business, net of cash sold				$ 50,051,000	$ 0
Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tax effect of discontinued operation	$ 2,000,000.0
Grass Valley
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accrued interest		$ 3,600,000
Revenues		1,000,000.0
Equity interest in divested business	$ 3,000,000.0
Equity interest in divested business, percentage	9.00%
Grass Valley | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment charges		0	$ 342,146,000	113,007,000	342,146,000
Capital expenditure, discontinued operations		300,000	8,300,000	16,700,000	22,800,000
Share-based compensation, discontinued operations		0.0	200,000	900,000	800,000
Accumulated other comprehensive income (loss), net of tax, discontinued operations						$ 42,300,000
Revenues		$ 1,334,000	$ 87,221,000	$ 109,195,000	$ 263,434,000
Grass Valley | Discontinued Operations, Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred compensation - earnout payments	$ 178,000,000.0
Proceeds from divestiture of businesses	120,000,000.0
Proceeds from disposal of business, net of cash sold	59,500,000
Deferred consideration - seller's note	175,000,000.0
Paid-in-Kind interest	88,000,000
Fair value of note	$ 34,900,000
Payment In Kind, Annual Interest Rate	0.085