Industry Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Number of reportable operating segments			2
Net sales	$ 268,875	$ 244,005	$ 480,586	$ 464,235
Intersegment revenue	0	0	0	0
Operating profit	22,690	23,294	32,393	35,732
Engine Management [Member]
Segment Reporting Information [Line Items]
Net sales	172,644	159,919	335,659	324,123
Intersegment revenue	4,358	4,907	8,846	10,468
Operating profit	17,630	13,443	31,318	28,263
Temperature Control [Member]
Segment Reporting Information [Line Items]
Net sales	93,036	79,715	138,327	133,794
Intersegment revenue	1,527	1,342	2,636	2,623
Operating profit	7,775	8,944	7,823	10,197
All Other [Member]
Segment Reporting Information [Line Items]
Net sales	3,195	4,371	6,600	6,318
Intersegment revenue	(5,885)	(6,249)	(11,482)	(13,091)
Operating profit	$ (2,715)	$ 907	$ (6,748)	$ (2,728)

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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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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- Definition

Amount of revenue from transactions with other operating segments of the same entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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