Intangible Assets, Net (Schedule of Finite-Lived and Indefinite-Lived Intangible Assets by Major Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization of Finite-Lived Intangible	$ (356,165)	$ (399,081)
Net Carrying Amount - Finite-Lived Intangible		516,990
Intangible Assets, Gross, Total	941,113	1,005,792
Intangible Assets, Net, Total	584,948	606,711
Customer Relationships And Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	689,935	710,932
Accumulated Amortization of Finite-Lived Intangible	(250,338)	(253,565)
Net Carrying Amount - Finite-Lived Intangible	439,597	457,367
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	15,821	15,778
Accumulated Amortization of Finite-Lived Intangible	(15,775)	(15,640)
Net Carrying Amount - Finite-Lived Intangible	46	138
Process Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	167,166	167,316
Accumulated Amortization of Finite-Lived Intangible	(89,831)	(86,256)
Net Carrying Amount - Finite-Lived Intangible	77,335	81,060
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	233	235
Accumulated Amortization of Finite-Lived Intangible	(221)	(183)
Net Carrying Amount - Finite-Lived Intangible	12	52
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	67,958	68,094
Aerospace [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization of Finite-Lived Intangible	(269,016)	(260,476)
Intangible Assets, Gross, Total	358,053	358,054
Intangible Assets, Net, Total	89,037	97,578
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	(203,451)	(196,520)
Net Carrying Amount - Finite-Lived Intangible	78,232	85,163
Aerospace [Member] | Process Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	76,370	76,371
Accumulated Amortization of Finite-Lived Intangible	(65,565)	(63,956)
Net Carrying Amount - Finite-Lived Intangible	10,805	12,415
Industrial [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization of Finite-Lived Intangible	(87,149)	(138,605)
Intangible Assets, Gross, Total	583,060	647,738
Intangible Assets, Net, Total	495,911	509,133
Industrial [Member] | Customer Relationships And Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	408,252	429,249
Accumulated Amortization of Finite-Lived Intangible	(46,887)	(57,045)
Net Carrying Amount - Finite-Lived Intangible	361,365	372,204
Industrial [Member] | Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	15,821	15,778
Accumulated Amortization of Finite-Lived Intangible	(15,775)	(15,640)
Net Carrying Amount - Finite-Lived Intangible	46	138
Industrial [Member] | Process Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	90,796	90,945
Accumulated Amortization of Finite-Lived Intangible	(24,266)	(22,300)
Net Carrying Amount - Finite-Lived Intangible	66,530	68,645
Industrial [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value - Finite-Lived Intangible	233	235
Accumulated Amortization of Finite-Lived Intangible	(221)	(183)
Net Carrying Amount - Finite-Lived Intangible	12	52
Industrial [Member] | Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	$ 67,958	$ 68,094