Consolidated Statements Of Stockholders' Equity (USD $) In Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total Jacobs Stockholders' Equity [Member]	Noncontrolling Interests [Member]	Total
Balances at Sep. 26, 2008	$ 122,701	$ 631,043	$ 1,620,673	$ (129,270)	$ 2,245,147	$ 6,178	$ 2,251,325
Net earnings			399,854		399,854	(641)	399,213
Foreign currency translation adjustments, net of deferred tax expense				4,744	4,744	25	4,769
FASB Statement No. 158 adjustment to remove early pension measurement date, net of deferred tax benefit			(5,735)	(982)	(6,717)		(6,717)
Pension liability, net of deferred tax expense				(81,845)	(81,845)		(81,845)
Other, miscellaneous elements of total comprehensive income (loss), net of deferred tax benefit				(4,162)	(4,162)		(4,162)
Issuances of equity securities, net	1,673	75,493			77,166		77,166
Repurchases of equity securities	(144)	(2,676)	(5,454)		(8,274)		(8,274)
Balances at Oct. 02, 2009	124,230	703,860	2,009,338	(211,515)	2,625,913	5,562	2,631,475
Net earnings			245,974		245,974	313	246,287
Foreign currency translation adjustments, net of deferred tax expense				(9,338)	(9,338)	5	(9,333)
Pension liability, net of deferred tax expense				(63,996)	(63,996)		(63,996)
Other, miscellaneous elements of total comprehensive income (loss), net of deferred tax benefit				(892)	(892)		(892)
Issuances of equity securities, net	1,802	66,635			68,437		68,437
Repurchases of equity securities	(123)	(2,981)	(3,946)		(7,050)		(7,050)
Balances at Oct. 01, 2010	125,909	767,514	2,251,366	(285,741)	2,859,048	5,880	2,864,928
Net earnings			331,029		331,029	4,192	335,221
Foreign currency translation adjustments, net of deferred tax expense				(25,024)	(25,024)		(25,024)
Pension liability, net of deferred tax expense				73,174	73,174		73,174
Other, miscellaneous elements of total comprehensive income (loss), net of deferred tax benefit				53	53		53
Noncontrolling interest acquired / consolidated						4,942	4,942
Distributions to noncontrolling interests						(4,617)	(4,617)
Issuances of equity securities, net	2,282	96,010			98,292		98,292
Repurchases of equity securities	(406)	(5,064)	(18,114)		(23,584)		(23,584)
Balances at Sep. 30, 2011	$ 127,785	$ 858,460	$ 2,564,281	$ (237,538)	$ 3,312,988	$ 10,397	$ 3,323,385