Intangible Assets, Net (Schedule of Finite-Lived Intangible Assets by Major Class) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Gross Carrying Value	$ 442,787		$ 442,787		$ 443,445
Accumulated Amortization	(258,210)		(258,210)		(245,795)
Net Carrying Amount	184,577		184,577		197,650
Amortization expense	6,431	$ 6,926	12,889	$ 13,872
Process Technology [Member]
Gross Carrying Value	99,326		99,326		99,570
Accumulated Amortization	(62,989)		(62,989)		(59,429)
Net Carrying Amount	36,337		36,337		40,141
Customer Relationships [Member]
Gross Carrying Value	323,085		323,085		323,194
Accumulated Amortization	(176,553)		(176,553)		(167,667)
Net Carrying Amount	146,532		146,532		155,527
Intellectual Property [Member]
Gross Carrying Value	19,190		19,190		19,435
Accumulated Amortization	(17,844)		(17,844)		(17,876)
Net Carrying Amount	1,346		1,346		1,559
Other Intangibles [Member]
Gross Carrying Value	1,186		1,186		1,246
Accumulated Amortization	(824)		(824)		(823)
Net Carrying Amount	362		362		423
Aerospace [Member]
Gross Carrying Value	358,830		358,830		358,830
Accumulated Amortization	(188,834)		(188,834)		(177,387)
Net Carrying Amount	169,996		169,996		181,443
Aerospace [Member] | Process Technology [Member]
Gross Carrying Value	76,605		76,605		76,605
Accumulated Amortization	(46,177)		(46,177)		(43,229)
Net Carrying Amount	30,428		30,428		33,376
Aerospace [Member] | Customer Relationships [Member]
Gross Carrying Value	282,225		282,225		282,225
Accumulated Amortization	(142,657)		(142,657)		(134,158)
Net Carrying Amount	139,568		139,568		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	83,957		83,957		84,615
Accumulated Amortization	(69,376)		(69,376)		(68,408)
Net Carrying Amount	14,581		14,581		16,207
Industrial [Member] | Process Technology [Member]
Gross Carrying Value	22,721		22,721		22,965
Accumulated Amortization	(16,812)		(16,812)		(16,200)
Net Carrying Amount	5,909		5,909		6,765
Industrial [Member] | Customer Relationships [Member]
Gross Carrying Value	40,860		40,860		40,969
Accumulated Amortization	(33,896)		(33,896)		(33,509)
Net Carrying Amount	6,964		6,964		7,460
Industrial [Member] | Intellectual Property [Member]
Gross Carrying Value	19,190		19,190		19,435
Accumulated Amortization	(17,844)		(17,844)		(17,876)
Net Carrying Amount	1,346		1,346		1,559
Industrial [Member] | Other Intangibles [Member]
Gross Carrying Value	1,186		1,186		1,246
Accumulated Amortization	(824)		(824)		(823)
Net Carrying Amount	$ 362		$ 362		$ 423