Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenues	$ 4,156,663	$ 2,514,751	$ 10,842,001	$ 7,368,922
Direct cost of contracts	(3,380,254)	(2,055,386)	(8,805,048)	(6,070,961)
Gross profit	776,409	459,365	2,036,953	1,297,961
Selling, general and administrative expenses	(563,680)	(330,890)	(1,630,294)	(1,012,685)
Operating Profit	212,729	128,475	406,659	285,276
Other Income (Expense):
Interest income	1,277	2,123	6,896	5,697
Interest expense	(23,787)	(4,054)	(50,106)	(11,327)
Miscellaneous income (expense), net	2,564	852	(6,582)	(5,879)
Total other (expense) income, net	(19,946)	(1,079)	(49,792)	(11,509)
Earnings Before Taxes	192,783	127,396	356,867	273,767
Income Tax Expense	(42,712)	(38,767)	(152,302)	(79,820)
Net Earnings of the Group	150,071	88,629	204,565	193,947
Net (Earnings) Loss Attributable to Noncontrolling Interests	151	403	(3,593)	5,639
Net Earnings Attributable to Jacobs	$ 150,222	$ 89,032	$ 200,972	$ 199,586
Net Earnings Per Share:
Basic (in dollars per share)	$ 1.05	$ 0.74	$ 1.47	$ 1.65
Diluted (in dollars per share)	$ 1.05	$ 0.74	$ 1.46	$ 1.64