Joint Ventures and VIE's (Schedule of Summarized Financial Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Schedule of Equity Method Investments [Line Items]
Current assets	$ 4,539,599	$ 4,111,768
Assets	12,354,353	11,462,711
Current liabilities	2,941,597	3,073,706
Joint ventures' equity	5,855,667	5,768,658	$ 5,944,354	$ 4,487,351
Total liabilities and stockholders' equity	12,354,353	11,462,711
Gross profit	2,586,668	2,477,028	2,158,550
Net earnings	523,867	873,219	173,142
Consolidated Entities
Schedule of Equity Method Investments [Line Items]
Revenue	912,900	571,600	481,400
Direct cost of contracts	(807,900)	(526,700)	(452,900)
Gross profit	105,000	44,900	28,500
Net earnings	72,600	45,200	28,400
VIE, primary beneficiary | Consolidated Entities
Schedule of Equity Method Investments [Line Items]
Current assets	261,600	192,600
Non-Current assets	200	0
Assets	261,800	192,600
Current liabilities	190,300	138,500
Non-current liabilities	0	0
Total liabilities	190,300	138,500
VIE, not primary beneficiary | Unconsolidated Joint Venture
Schedule of Equity Method Investments [Line Items]
Current assets	1,697,000	1,443,500
Non-Current assets	34,900	29,900
Assets	1,731,900	1,473,400
Current liabilities	889,700	692,100
Non-current liabilities	631,000	473,600
Total liabilities	1,520,700	1,165,700
Joint ventures' equity	211,200	307,700
Total liabilities and stockholders' equity	1,731,900	1,473,400
Revenue	3,447,000	3,533,100	3,165,000
Direct cost of contracts	(3,126,600)	(3,176,200)	(2,902,500)
Gross profit	320,400	356,900	262,500
Net earnings	$ 245,300	$ 227,000	$ 221,100