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
Beginning balance at Oct. 01, 2021	$ 5,974,837	$ 5,940,041	$ 128,893	$ 2,590,012	$ 4,015,578	$ (794,442)	$ 34,796
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	143,286	134,034			134,034		9,252
Foreign currency translation adjustments, net of deferred taxes	(5,695)	(5,695)				(5,695)
Pension and retiree medical plan liability, net of deferred taxes	6,571	6,571				6,571
Gain (loss) on derivatives, net of deferred taxes	5,910	5,910				5,910
Dividends	(123)	(123)			(123)
Redeemable Noncontrolling interests redemption value adjustment	(15,203)	(15,203)			(15,203)
Repurchase and issuance of redeemable noncontrolling interests	7,761	7,761			7,761
Noncontrolling interests - distributions and other	(14,049)						(14,049)
Stock based compensation	7,014	7,014		7,014
Issuances of equity securities including shares withheld for taxes	(10,364)	(10,364)	602	906	(11,872)
Repurchases of equity securities	0	0	(342)	43,127	(42,785)
Ending balance at Dec. 31, 2021	6,099,945	6,069,946	129,153	2,641,059	4,087,390	(787,656)	29,999
Beginning balance 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	142,678	135,647			135,647		7,031
Foreign currency translation adjustments, net of deferred taxes	158,726	158,726				158,726
Pension and retiree medical plan liability, net of deferred taxes	(22,574)	(22,574)				(22,574)
Gain (loss) on derivatives, net of deferred taxes	(6,874)	(6,874)				(6,874)
Dividends	(874)	(874)			(874)
Redeemable Noncontrolling interests redemption value adjustment	(23,317)	(23,317)			(23,317)
Repurchase and issuance of redeemable noncontrolling interests	11,337	11,337			11,337
Noncontrolling interests - distributions and other	(1,873)						(1,873)
Stock based compensation	20,231	20,231		20,231
Issuances of equity securities including shares withheld for taxes	(7,732)	(7,732)	514	(3,762)	(4,484)
Repurchases of equity securities	(140,522)	(140,522)	(1,238)	(26,057)	(113,227)
Ending balance at Dec. 30, 2022	$ 6,233,598	$ 6,184,104	$ 126,669	$ 2,672,421	$ 4,230,866	$ (845,852)	$ 49,494