BUSINESS SEGMENT INFORMATION (Schedule Of Net Sales And Earnings Before Income Tax) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Net sales	$ 116,922	$ 118,432	$ 345,478	$ 355,148
Consolidated EBIT	11,411	16,541	31,186	39,544
Less: Interest expense	(778)	(1,014)	(1,997)	(1,989)
Earnings before income taxes	10,633	15,527	29,189	37,555
USG [Member]
Segment Reporting Information [Line Items]
Net sales	26,597	25,666	79,059	80,418
Consolidated EBIT	5,132	9,203	14,735	19,894
Test [Member]
Segment Reporting Information [Line Items]
Net sales	36,562	41,815	112,678	131,652
Consolidated EBIT	3,844	2,395	6,922	9,117
Filtration [Member]
Segment Reporting Information [Line Items]
Net sales	53,763	50,951	153,741	143,078
Consolidated EBIT	10,689	11,228	30,384	28,932
Corporate (Loss) [Member]
Segment Reporting Information [Line Items]
Consolidated EBIT	$ (8,254)	$ (6,285)	$ (20,855)	$ (18,399)

Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(1)(i))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

This element represents the income or loss from continuing operations (before interest income and interest expense) attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before interest income, interest expense, income taxes, extraordinary items, and noncontrolling interest.

+ References

No definition available.

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- Definition

The net amount of operating interest income (expense).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.10)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 10

-Article 9

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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