Goodwill and Intangible Assets (Tables)

6 Months Ended

Mar. 31, 2024

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of changes in the carrying value of goodwill

The following table summarizes the changes in the carrying value of goodwill by reportable segment (in thousands):

	GSG		CIG		Total
Balance at October 1, 2023	$	659,942	$	1,220,302	$	1,880,244
Acquisition activity	71,100		—		71,100
Translation adjustments	2,155		24,189		26,344
Balance at March 31, 2024	$	733,197	$	1,244,491	$	1,977,688

Summary of acquired identifiable intangible assets with finite useful lives

The following table presents the gross amount and accumulated amortization of our acquired identifiable intangible assets with finite useful lives included in “Intangible assets, net” on the consolidated balance sheets ($ in thousands):

	Period Ended
	March 31, 2024							October 1, 2023
	Weighted- Average Remaining Life (in Years)	Gross Amount		Accumulated Amortization		Net Amount		Gross Amount		Accumulated Amortization		Net Amount
Client relations	8.7	$	188,940	$	(45,970)	$	142,970	$	169,217	$	(36,072)	$	133,145
Backlog	0.7	71,161		(58,761)		12,400		63,825		(47,802)		16,023
Trade names	1.9	38,633		(18,392)		20,241		37,411		(12,643)		24,768
Total		$	298,734	$	(123,123)	$	175,611	$	270,453	$	(96,517)	$	173,936

Estimated amortization expense for the remainder of the fiscal year and the succeeding years

Estimated amortization expense for the remainder of fiscal 2024 and succeeding years is as follows (in thousands):

	Amount
2024 (remaining)	$	24,255
2025	33,499
2026	22,916
2027	16,806
2028	16,296
Beyond	61,839
Total	$	175,611