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Goodwill and Intangible Assets Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
	Apr. 28, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022
Finite-Lived Intangible Assets [Line Items]
Cost		$ 532,254		$ 444,737
Accumulated Amortization		(354,920)		(332,472)
Net		177,334		112,265
Purchases of intangible assets			$ 11,500
Weighted-Average Useful Life (Years)			16 years
MPEG LA, L.L.C.
Finite-Lived Intangible Assets [Line Items]
Weighted-Average Useful Life (Years)	12 years
Identifiable intangible assets acquired		86,000
Acquired patents and technology
Finite-Lived Intangible Assets [Line Items]
Cost		357,032		355,622
Accumulated Amortization		(271,322)		(253,080)
Net		85,710		102,542
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost		152,190		66,142
Accumulated Amortization		(60,617)		(56,572)
Net		91,573		9,570
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Cost		23,032		22,973
Accumulated Amortization		(22,981)		(22,820)
Net		$ 51		$ 153