Business Segment Information (Schedule Of Depreciation And Amortization) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Depreciation and Amortization	$ 16,362	$ 14,805	$ 14,495
Filtration [Member]
Depreciation and Amortization	5,200	4,200	3,900
Test [Member]
Depreciation and Amortization	2,700	2,500	2,500
USG [Member]
Depreciation and Amortization	4,800	4,600	3,400
Corporate [Member]
Depreciation and Amortization	$ 3,700	$ 3,500	$ 4,700