Business Segment Information (Schedule Of Earnings Before Income Tax) (Details) (USD $)	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Segment Reporting Information [Line Items]
Consolidated EBIT	$ 79,500,000	$ 73,600,000	$ 70,600,000
Less: interest expense	(2,493,000)	(3,977,000)	(7,450,000)
Earnings before income tax	76,958,000	69,665,000	63,172,000
Utility Solutions [Member]
Segment Reporting Information [Line Items]
Consolidated EBIT	54,300,000	67,400,000	62,500,000
Test [Member]
Segment Reporting Information [Line Items]
Consolidated EBIT	18,600,000	12,200,000	14,100,000
Filtration [Member]
Segment Reporting Information [Line Items]
Consolidated EBIT	30,800,000	19,500,000	18,100,000
Corporate (Loss) [Member]
Segment Reporting Information [Line Items]
Consolidated EBIT	$ (24,200,000)	$ (25,500,000)	$ (24,100,000)

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 SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 08

-Paragraph h

-Subparagraph 1(i)

Reference 2: 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=6881521&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.

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- Definition

The net amount of operating interest income (expense).

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 10

-Article 9

Reference 2: 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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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