Business Segment Information (Schedule Of Net Sales And Earnings Before Income Tax) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net sales	$ 159,505	$ 140,191	$ 138,930	$ 132,833	$ 153,612	$ 134,191	$ 128,941	$ 120,547	$ 571,459	$ 537,291	$ 531,120
Consolidated EBIT									69,700	62,300	63,800
Less: Interest expense									(1,308)	(785)	(1,567)
Earnings before income taxes									68,420	61,521	62,207
Filtration [Member]
Segment Reporting Information [Line Items]
Net sales									207,800	196,700	196,500
Consolidated EBIT									45,200	41,700	36,400
Technical Packaging [Member]
Segment Reporting Information [Line Items]
Net sales									74,400	39,400	37,200
Consolidated EBIT									9,600	4,900	5,000
Test [Member]
Segment Reporting Information [Line Items]
Net sales									161,500	177,600	181,800
Consolidated EBIT									13,900	9,500	21,100
Utility Solutions [Member]
Segment Reporting Information [Line Items]
Net sales									127,800	123,600	115,600
Consolidated EBIT									31,100	29,600	26,600
Corporate (loss) [Member]
Segment Reporting Information [Line Items]
Consolidated EBIT									$ (30,100)	$ (23,400)	$ (25,300)