CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Total Jacobs Stockholders’ Equity	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Balance at the beginning of the period at Sep. 30, 2022	$ 6,104,392	$ 6,060,056	$ 127,393	$ 2,682,009	$ 4,225,784	$ (975,130)	$ 44,336
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	698,042	665,777			665,777		32,265
Foreign currency translation adjustments, net of deferred taxes	150,103	150,103				150,103
Pension plan liability, net of deferred taxes	(18,297)	(18,297)				(18,297)
Change in cash flow hedges, net of deferred taxes	(14,630)	(14,630)				(14,630)
Dividends	(132,468)	(132,468)			(132,468)
Noncontrolling interests - distributions and other	(22,739)						(22,739)
Redeemable Noncontrolling interests redemption value adjustment	(10,770)	(10,770)			(10,770)
Repurchase and issuance of redeemable noncontrolling interests	14,293	14,293			14,293
Stock based compensation	74,337	74,337		74,337
Issuances of equity securities including shares withheld for taxes	23,533	23,533	910	28,181	(5,558)
Repurchases of equity securities	(265,714)	(265,714)	(2,326)	(49,202)	(214,186)
Balance at the end of the period at Sep. 29, 2023	6,600,082	6,546,220	125,977	2,735,325	4,542,872	(857,954)	53,862
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	837,644	806,093			806,093		31,551
Foreign currency translation adjustments, net of deferred taxes	211,702	211,702				211,702
Pension plan liability, net of deferred taxes	(44,998)	(44,998)				(44,998)
Change in cash flow hedges, net of deferred taxes	(62,672)	(62,672)				(62,672)
Dividends	(145,924)	(145,924)			(145,924)
Noncontrolling interests - distributions and other	(21,202)						(21,202)
Redeemable Noncontrolling interests redemption value adjustment	(171,142)	(171,142)			(171,142)
Repurchase and issuance of redeemable noncontrolling interests	4,698	4,698			4,698
Distribution adjustments relating to SpinCo Business	(2,318,193)	(2,271,818)			(2,326,290)	54,472	(46,375)
Stock based compensation	74,193	74,193		74,193
Issuances of equity securities including shares withheld for taxes	5,783	5,783	994	11,512	(6,723)
Repurchases of equity securities	(402,668)	(402,668)	(2,887)	(62,966)	(336,815)
Balance at the end of the period at Sep. 27, 2024	4,567,303	4,549,467	124,084	2,758,064	2,366,769	(699,450)	17,836
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	292,779	289,336			289,336		3,443
Foreign currency translation adjustments, net of deferred taxes	(4,453)	(4,453)				(4,453)
Pension plan liability, net of deferred taxes	(1,973)	(1,973)				(1,973)
Change in cash flow hedges, net of deferred taxes	(4,534)	(4,534)				(4,534)
Dividends	(117,977)	(117,977)			(117,977)
Dividend in kind	(159,266)	(159,266)			(159,266)
Noncontrolling interests - distributions and other	(14,181)						(14,181)
Redeemable Noncontrolling interests redemption value adjustment	(199,763)	(199,763)			(199,763)
Repurchase and issuance of redeemable noncontrolling interests	3,550	3,550			3,550
Distribution adjustments relating to SpinCo Business	(27,672)	(27,672)			(27,672)
Stock based compensation	60,960	60,960		60,960
Issuances of equity securities including shares withheld for taxes	7,262	7,262	685	14,230	(7,653)
Repurchases of equity securities	(754,130)	(754,130)	(5,688)	(126,878)	(621,564)
Balance at the end of the period at Sep. 26, 2025	$ 3,647,905	$ 3,640,807	$ 119,081	$ 2,706,376	$ 1,525,760	$ (710,410)	$ 7,098