Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net Earnings of the Group	$ 88,629	$ 70,937	$ 193,947	$ 184,632
Other Comprehensive Income (Loss):
Foreign currency translation adjustment	66,763	(35,840)	(179,320)	(35,094)
(Loss) gain on cash flow hedges	(4,386)	(459)	362	(872)
Change in pension liabilities	(13,991)	42,008	8,304	60,426
Other comprehensive income (loss) before taxes	48,386	5,709	(170,654)	24,460
Income Tax (Expense) Benefit:
Cash flow hedges	1,016	(69)	(90)	(65)
Change in pension liabilities	2,220	(8,706)	(2,049)	(12,893)
Income Tax Benefit (Expense):	3,236	(8,775)	(2,139)	(12,958)
Net other comprehensive income (loss)	51,622	(3,066)	(172,793)	11,502
Net Comprehensive Income of the Group	140,251	67,871	21,154	196,134
Net Earnings (Losses) Attributable to Noncontrolling Interests	403	(1,882)	5,639	(3,813)
Net Comprehensive Income Attributable to Jacobs	$ 140,654	$ 65,989	$ 26,793	$ 192,321