Income Taxes (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended					6 Months Ended	9 Months Ended		12 Months Ended
	Jan. 01, 2018	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Mar. 29, 2019	Jun. 28, 2019	Jun. 29, 2018	Sep. 28, 2018
Income Tax Contingency [Line Items]
Federal tax rate	21.00%					35.00%
Provision for income taxes		$ 2,163			$ (9,067)			$ 14,486	$ 163,070
Tax Cuts and Jobs Act, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense		2,300	$ (19,000)	$ 36,000			$ (19,000)	2,300		$ (121,400)
Tax Cuts and Jobs Act, transition tax for accumulated foreign earnings, income tax expense1		102,100
Unrecognized tax benefits, gross		107,500						107,500		102,000
Unrecognized tax benefits if recognized, would affect our effective tax rate		$ 72,700						72,700		96,900
Unrecognized tax benefits, period increase (decrease)								$ 9,400
Effective tax rate (as a percent)		5.20%			156.10%			6.40%	91.30%
Impact Of Tax Cuts And Jobs Act [Member]
Income Tax Contingency [Line Items]
Provision for income taxes										121,400
Impact Of Tax Cuts And Jobs Act, Repatriation Transition Tax [Member]
Income Tax Contingency [Line Items]
Increase (Decrease) in Deferred Income Taxes				36,000
Deferred tax assets, gross										$ 33,600
Effect of Adopting ASC 606
Income Tax Contingency [Line Items]
Increase (Decrease) in Deferred Income Taxes				$ (26,300)