Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Total AECOM Stockholders’ Equity	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficits	Non- Controlling Interests
Beginning balance at Sep. 30, 2023	$ 2,383,711	$ 2,212,332	$ 1,362	$ 4,241,523	$ (926,577)	$ (1,103,976)	$ 171,379
Increase (Decrease) in Stockholders' Equity
Net income (loss)	108,594	94,438				94,438	14,156
Dividends declared	(30,074)	(30,074)				(30,074)
Other comprehensive income (loss)	36,954	36,789			36,789		165
Issuance of stock	10,897	10,897	9	10,888
Repurchases of stock	(92,138)	(92,138)	(11)	(22,123)		(70,004)
Stock-based compensation	15,052	15,052		15,052
Contributions from noncontrolling interests	2,876						2,876
Distributions to noncontrolling interests	(7,654)						(7,654)
Ending balance at Dec. 31, 2023	2,428,218	2,247,296	1,360	4,245,340	(889,788)	(1,109,616)	180,922
Beginning balance at Sep. 30, 2024	2,370,410	2,184,205	1,326	4,347,197	(882,671)	(1,281,647)	186,205
Increase (Decrease) in Stockholders' Equity
Net income (loss)	179,204	167,042				167,042	12,162
Dividends declared	(34,614)	(34,614)				(34,614)
Other comprehensive income (loss)	(82,511)	(82,123)			(82,123)		(388)
Issuance of stock	6,331	6,331	5	6,326
Repurchases of stock	(53,654)	(53,654)	(5)	(18,383)		(35,266)
Stock-based compensation	16,823	16,823		16,823
Contributions from noncontrolling interests	10						10
Distributions to noncontrolling interests	(2,456)						(2,456)
Ending balance at Dec. 31, 2024	$ 2,399,543	$ 2,204,010	$ 1,326	$ 4,351,963	$ (964,794)	$ (1,184,485)	$ 195,533