Intangible Assets, Net (Schedule of Finite-Lived and Indefinite-Lived Intangible Assets by Major Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross, Total	$ 979,433	$ 983,266
Accumulated Amortization of Finite-Lived Intangible	(366,298)	(371,274)
Net Carrying Amount - Finite-Lived Intangible	548,162
Intangible Assets, Net, Total	613,135	611,992
Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	64,973	63,467
Customer Relationships And Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	693,119	689,366
Accumulated Amortization of Finite-Lived Intangible	(229,245)	(225,981)
Net Carrying Amount - Finite-Lived Intangible	463,874	463,385
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	15,790	19,201
Accumulated Amortization of Finite-Lived Intangible	(15,513)	(18,705)
Net Carrying Amount - Finite-Lived Intangible	277	496
Process Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	163,871	169,191
Accumulated Amortization of Finite-Lived Intangible	(79,966)	(84,839)
Net Carrying Amount - Finite-Lived Intangible	83,905	84,352
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	41,456	40,500
Accumulated Amortization of Finite-Lived Intangible	(41,456)	(40,500)
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	224	1,541
Accumulated Amortization of Finite-Lived Intangible	(118)	(1,249)
Net Carrying Amount - Finite-Lived Intangible	106	292
Aerospace [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross, Total	358,054	358,054
Accumulated Amortization of Finite-Lived Intangible	(246,550)	(241,908)
Intangible Assets, Net, Total	111,504	116,146
Aerospace [Member] | Customer Relationships And Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	281,683	281,683
Accumulated Amortization of Finite-Lived Intangible	(185,626)	(181,995)
Net Carrying Amount - Finite-Lived Intangible	96,057	99,688
Aerospace [Member] | Process Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	76,371	76,371
Accumulated Amortization of Finite-Lived Intangible	(60,924)	(59,913)
Net Carrying Amount - Finite-Lived Intangible	15,447	16,458
Industrial [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross, Total	621,379	625,212
Accumulated Amortization of Finite-Lived Intangible	(119,748)	(129,366)
Intangible Assets, Net, Total	501,631	495,846
Industrial [Member] | Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	64,973	63,467
Industrial [Member] | Customer Relationships And Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	411,436	407,683
Accumulated Amortization of Finite-Lived Intangible	(43,619)	(43,986)
Net Carrying Amount - Finite-Lived Intangible	367,817	363,697
Industrial [Member] | Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	15,790	19,201
Accumulated Amortization of Finite-Lived Intangible	(15,513)	(18,705)
Net Carrying Amount - Finite-Lived Intangible	277	496
Industrial [Member] | Process Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	87,500	92,820
Accumulated Amortization of Finite-Lived Intangible	(19,042)	(24,926)
Net Carrying Amount - Finite-Lived Intangible	68,458	67,894
Industrial [Member] | Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	41,456	40,500
Accumulated Amortization of Finite-Lived Intangible	(41,456)	(40,500)
Net Carrying Amount - Finite-Lived Intangible	0	0
Industrial [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	224	1,541
Accumulated Amortization of Finite-Lived Intangible	(118)	(1,249)
Net Carrying Amount - Finite-Lived Intangible	$ 106	$ 292