Business Segment Information (Schedule Of Net Sales) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Net sales	$ 152,925	$ 159,936
Test [Member]
Segment Reporting Information [Line Items]
Net sales	39,354	32,004
Filtration [Member]
Segment Reporting Information [Line Items]
Net sales	43,222	35,743
USG Segment [Member]
Segment Reporting Information [Line Items]
Net sales	$ 70,349	$ 92,189

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.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

Reference 2: 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=6880815&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration