Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	6 years
Carrying amount, finite-lived intangible assets	$ 520,108	$ 502,611
Accumulated Amortization	(264,240)	(226,851)
Total	255,868	275,760
Indefinite‑lived intangible assets	34,207	34,207
Carrying amount, intangible assets	554,315	536,818
Intangible assets, net	$ 290,075	309,967
Customer related
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	9 years
Carrying amount, finite-lived intangible assets	$ 300,963	292,316
Accumulated Amortization	(101,272)	(83,486)
Total	$ 199,691	208,830
Proprietary technology
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	4 years
Carrying amount, finite-lived intangible assets	$ 61,692	61,990
Accumulated Amortization	(36,921)	(30,886)
Total	$ 24,771	31,104
Trademark
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	6 years
Carrying amount, finite-lived intangible assets	$ 27,195	27,114
Accumulated Amortization	(12,191)	(9,142)
Total	15,004	17,972
Backlog
Finite-Lived Intangible Assets [Line Items]
Carrying amount, finite-lived intangible assets	82,355	82,181
Accumulated Amortization	(82,355)	(82,181)
Total	$ 0	$ 0
Finite-lived intangible asset, useful life	1 year	1 year
Other
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets, weighted average useful life	2 years
Carrying amount, finite-lived intangible assets	$ 47,903	$ 39,010
Accumulated Amortization	(31,501)	(21,156)
Total	$ 16,402	$ 17,854
Finite-lived intangible asset, useful life		3 years
Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	1 year
Minimum | Customer related
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	5 years	5 years
Minimum | Proprietary technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	7 years	7 years
Minimum | Trademark
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	5 years	5 years
Minimum | Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	26 years
Maximum | Customer related
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	26 years	26 years
Maximum | Proprietary technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years	10 years
Maximum | Trademark
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	15 years	15 years
Maximum | Other
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years