CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 28, 2025	Mar. 29, 2024	Mar. 28, 2025	Mar. 29, 2024
Statement of Comprehensive Income [Abstract]
Net (Loss) Earnings of the Group	$ (303)	$ 173,534	$ (5,305)	$ 354,989
Other Comprehensive Income:
Foreign currency translation adjustments	64,040	(34,872)	(96,108)	73,177
Change in cash flow hedges	(6,229)	1,925	(408)	(25,741)
Change in pension plan liabilities	(6,672)	4,294	17,504	(6,459)
Other comprehensive income (loss) before taxes	51,139	(28,653)	(79,012)	40,977
Income Tax Benefit (Expense):
Cash flow hedges	1,735	(526)	251	6,669
Change in pension plan liabilities	(700)	(473)	(1,832)	(935)
Income Tax Benefit (Expense):	1,035	(999)	(1,581)	5,734
Net other comprehensive Income (loss)	52,174	(29,652)	(80,593)	46,711
Net Comprehensive Income (Loss) of the Group	51,871	143,882	(85,898)	401,700
Net Loss (Earnings) Attributable to Noncontrolling Interests	11,731	(7,340)	5,651	(14,567)
Net Earnings Attributable to Redeemable Noncontrolling interests	(5,816)	(4,082)	(12,863)	(6,700)
Net Comprehensive Income (Loss) Attributable to Jacobs	$ 57,786	$ 132,460	$ (93,110)	$ 380,433