Consolidated Statements Of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comp- rehensive Income (Loss)	Total Jacobs Stock- holders’ Equity	Non- controlling Interests
Balances at Sep. 28, 2012	$ 3,758,889	$ 129,936	$ 953,983	$ 2,920,441	$ (281,887)	$ 3,722,473	$ 36,416
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	440,182			423,093		423,093	17,089
Foreign currency translation adjustments, net of deferred tax	(23,704)				(23,704)	(23,704)
Pension liability, net of deferred tax	547				547	547
Gain on derivatives, net of deferred tax	917				917	917
Noncontrolling interest acquired / consolidated	794		11,087	0		11,087	(10,293)
Distributions to noncontrolling interests	(7,974)						(7,974)
Issuances of equity securities, net of deferred tax	140,456	2,864	137,592	0		140,456
Repurchases of equity securities	(61,772)	(1,161)	(18,038)	(42,573)		(61,772)
Balances at Sep. 27, 2013	4,248,335	131,639	1,084,624	3,300,961	(304,127)	4,213,097	35,238
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	352,112			328,108		328,108	24,004
Foreign currency translation adjustments, net of deferred tax	(30,066)				(30,066)	(30,066)
Pension liability, net of deferred tax	(29,865)				(29,865)	(29,865)
Gain on derivatives, net of deferred tax	509				509	509
Noncontrolling interest acquired / consolidated	(28,649)		4,779	(15,704)		(10,925)	(17,724)
Distributions to noncontrolling interests	(6,081)			(968)		(968)	(5,113)
Issuances of equity securities, net of deferred tax	117,207	2,254	114,953			117,207
Repurchases of equity securities	(117,842)	(2,140)	(30,498)	(85,204)		(117,842)
Balances at Sep. 26, 2014	4,505,660	131,753	1,173,858	3,527,193	(363,549)	4,469,255	36,405
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	328,882			302,971		302,971	25,911
Foreign currency translation adjustments, net of deferred tax	(136,168)				(136,168)	(136,168)
Pension liability, net of deferred tax	32,770				32,770	32,770
Gain on derivatives, net of deferred tax	2,183				2,183	2,183
Noncontrolling interest acquired / consolidated	(82)		0	(9,709)		(9,709)	9,627
Distributions to noncontrolling interests	(7,230)			0		0	(7,230)
Issuances of equity securities, net of deferred tax	82,391	1,590	80,801			82,391
Repurchases of equity securities	(451,948)	(10,190)	(117,515)	(324,243)		(451,948)
Balances at Oct. 02, 2015	$ 4,356,458	$ 123,153	$ 1,137,144	$ 3,496,212	$ (464,764)	$ 4,291,745	$ 64,713