Goodwill And Other Intangible Assets (Schedule Of Changes In The Carrying Amount Of Goodwill Attributable To Business Segment (Details) (USD $)	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 355,656,000	$ 330,700,000
Acquisitions/adjustments	6,200,000	25,000,000
Goodwill, Ending Balance	361,864,000	355,656,000
USG [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	296,100,000	279,900,000
Acquisitions/adjustments	1,700,000	16,200,000
Goodwill, Ending Balance	297,800,000	296,100,000
Test [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	30,500,000	30,500,000
Acquisitions/adjustments	4,300,000
Goodwill, Ending Balance	34,800,000	30,500,000
Filtration [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance	29,100,000	20,300,000
Acquisitions/adjustments	200,000	8,800,000
Goodwill, Ending Balance	$ 29,300,000	$ 29,100,000

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

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-Subparagraph e

-Clause 1

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-Name Statement of Financial Accounting Standard (FAS)

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-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph l

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

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-Section 50

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-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

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