Intangible Assets, Net (Schedule of Finite-Lived Intangible Assets by Major Class) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Gross Carrying Value	$ 443,490		$ 443,490		$ 443,445
Accumulated Amortization	(265,153)		(265,153)		(245,795)
Net Carrying Amount	178,337		178,337		197,650
Amortization expense	6,439	$ 6,887	19,328	$ 20,759
Process Technology [Member]
Gross Carrying Value	99,648		99,648		99,570
Accumulated Amortization	(65,084)		(65,084)		(59,429)
Net Carrying Amount	34,564		34,564		40,141
Customer Relationships [Member]
Gross Carrying Value	323,228		323,228		323,194
Accumulated Amortization	(181,119)		(181,119)		(167,667)
Net Carrying Amount	142,109		142,109		155,527
Intellectual Property [Member]
Gross Carrying Value	19,344		19,344		19,435
Accumulated Amortization	(18,047)		(18,047)		(17,876)
Net Carrying Amount	1,297		1,297		1,559
Other Intangibles [Member]
Gross Carrying Value	1,270		1,270		1,246
Accumulated Amortization	(903)		(903)		(823)
Net Carrying Amount	367		367		423
Aerospace [Member]
Gross Carrying Value	358,830		358,830		358,830
Accumulated Amortization	(194,556)		(194,556)		(177,387)
Net Carrying Amount	164,274		164,274		181,443
Aerospace [Member] | Process Technology [Member]
Gross Carrying Value	76,605		76,605		76,605
Accumulated Amortization	(47,651)		(47,651)		(43,229)
Net Carrying Amount	28,954		28,954		33,376
Aerospace [Member] | Customer Relationships [Member]
Gross Carrying Value	282,225		282,225		282,225
Accumulated Amortization	(146,905)		(146,905)		(134,158)
Net Carrying Amount	135,320		135,320		148,067
Aerospace [Member] | Intellectual Property [Member]
Gross Carrying Value	0		0		0
Accumulated Amortization	0		0		0
Net Carrying Amount	0		0		0
Aerospace [Member] | Other Intangibles [Member]
Gross Carrying Value	0		0		0
Accumulated Amortization	0		0		0
Net Carrying Amount	0		0		0
Industrial [Member]
Gross Carrying Value	84,660		84,660		84,615
Accumulated Amortization	(70,597)		(70,597)		(68,408)
Net Carrying Amount	14,063		14,063		16,207
Industrial [Member] | Process Technology [Member]
Gross Carrying Value	23,043		23,043		22,965
Accumulated Amortization	(17,433)		(17,433)		(16,200)
Net Carrying Amount	5,610		5,610		6,765
Industrial [Member] | Customer Relationships [Member]
Gross Carrying Value	41,003		41,003		40,969
Accumulated Amortization	(34,214)		(34,214)		(33,509)
Net Carrying Amount	6,789		6,789		7,460
Industrial [Member] | Intellectual Property [Member]
Gross Carrying Value	19,344		19,344		19,435
Accumulated Amortization	(18,047)		(18,047)		(17,876)
Net Carrying Amount	1,297		1,297		1,559
Industrial [Member] | Other Intangibles [Member]
Gross Carrying Value	1,270		1,270		1,246
Accumulated Amortization	(903)		(903)		(823)
Net Carrying Amount	$ 367		$ 367		$ 423