Industry Segments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) Segment	Jun. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable operating segments | Segment			2
Net sales	$ 288,977	$ 269,382	$ 527,888	$ 496,971
Operating Income	31,844	21,312	51,863	36,227
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Engine Management [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net sales	198,848	176,992	379,529	354,063
Operating Income	30,548	21,839	54,752	43,555
Engine Management [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	5,817	5,030	10,689	10,053
Temperature Control [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Net sales	87,503	89,079	144,269	137,807
Operating Income	5,647	3,165	7,814	1,746
Temperature Control [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	2,121	1,925	3,715	3,369
All Other [Member]
Segment Reporting Information [Line Items]
Net sales	2,626	3,311	4,090	5,101
Operating Income	(4,351)	(3,692)	(10,703)	(9,074)
All Other [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	$ (7,938)	$ (6,955)	$ (14,404)	$ (13,422)