Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information, Profit (Loss)
Revenues	$ 194,093	$ 141,369		$ 533,035	$ 391,153
Gross profit	43,843	21,864		98,458	72,605
Income before income taxes	18,279	1,195	1,195	30,120	8,177
Depreciation and amortization expense	3,387	3,990		9,814	11,448
Electrical Power Products [Member]
Segment Reporting Information, Profit (Loss)
Revenues	186,272	134,425		510,910	370,143
Gross profit	41,677	19,788		93,203	67,236
Income before income taxes	18,422	1,055		30,066	8,567
Depreciation and amortization expense	3,365	3,951		9,779	11,325
Process Control Systems [Member]
Segment Reporting Information, Profit (Loss)
Revenues	7,821	6,944		22,125	21,010
Gross profit	2,166	2,076		5,255	5,369
Income before income taxes	(143)	140		54	(390)
Depreciation and amortization expense	$ 22	$ 39		$ 35	$ 123

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

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- Definition

This element represents the income or loss from continuing operations 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 income taxes, extraordinary items, and noncontrolling interest.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

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- Definition

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

+ 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=6880815&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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