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Segment Information - Revenue and Long-lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 29, 2017	Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 3,392,862	$ 3,169,622	$ 3,091,596	$ 3,083,788	$ 2,991,856	$ 2,933,623	$ 2,870,295	$ 1,783,999	$ 12,737,868	$ 10,579,773	$ 6,330,126
Property, equipment and improvements, net	308,143				257,859				308,143	257,859
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									9,006,730	6,908,988	3,881,696
Property, equipment and improvements, net	230,476				118,073				230,476	118,073
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									2,242,976	2,495,805	1,754,036
Property, equipment and improvements, net	52,775				58,739				52,775	58,739
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									213,172	189,865	6,531
Property, equipment and improvements, net	3,199				21,559				3,199	21,559
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									195,023	163,761	111,646
Property, equipment and improvements, net	5,652				3,588				5,652	3,588
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									62,543	52,533	40,469
Property, equipment and improvements, net	2,379				19,446				2,379	19,446
Australia and New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									533,251	578,108	519,575
Property, equipment and improvements, net	12,091				16,151				12,091	16,151
South America and Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									7,416	17,656	244
Property, equipment and improvements, net	0				3,650				0	3,650
Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									476,757	173,057	$ 15,929
Property, equipment and improvements, net	$ 1,571				$ 16,653				$ 1,571	$ 16,653