Business Divestiture - Narrative (Details) - USD ($) $ in Thousands			3 Months Ended			9 Months Ended
		May 14, 2020	Sep. 27, 2020	Dec. 29, 2019	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	[1]					$ 15,418	$ 40,491
Gain on disposition			$ 0		$ 0	10,458	143,400
Tax expense			36,725		$ 2,928	38,716	$ 10,074
NovaSource
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses						16,000
Escrow holdback reserve			$ 5,300			$ 5,300
Holdback related to business divestitures		$ 15,000
Amortization period, contract cost			3 years			3 years
Operations and maintenance | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses				$ 36,300
Working capital adjustment, upon close			$ 5,324			$ 5,324
Gain on disposition						10,500
Tax expense			$ 2,100			2,100
Transaction expense						$ 2,700

[1] Amount for the nine months ended September 27, 2020 is net of de-consolidated cash of $0.6 million