Industry Segment and Geographic Data (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) Customer Segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Reporting Information [Line Items]
Number of reportable operating segments | Segment									2
Financial information for reportable segment [Abstract]
Net sales									$ 971,975	$ 980,392	$ 983,704
Depreciation and amortization									17,637	17,295	17,595
Operating income (loss)									75,860	85,338	86,863
Investment in equity affiliates	$ 20,622				$ 20,004				20,622	20,004	6,308
Capital expenditures									18,047	13,904	11,410
Total assets	681,064				673,551				681,064	673,551	615,523
Reconciliation of segment operating income to net earnings [Abstract]
Operating income									75,860	85,338	86,863
Other non-operating income (expense)									(220)	(1,969)	1
Interest expense									1,537	1,616	1,902
Earnings from continuing operations before taxes									74,103	81,753	84,962
Income tax expense									25,983	28,854	31,919
Earnings from continuing operations	5,779	$ 19,194	$ 13,808	$ 9,339	11,517	$ 17,806	$ 11,169	$ 12,407	48,120	52,899	53,043
Discontinued operations, net of tax	(553)	(728)	(430)	(391)	(419)	(8,240)	(529)	(682)	(2,102)	(9,870)	(1,593)
Net earnings	5,226	18,466	13,378	8,948	11,098	9,566	10,640	11,725	46,018	43,029	51,450
Revenues [Abstract]
Revenues	204,967	$ 270,037	$ 269,382	$ 227,589	218,054	$ 257,046	272,540	$ 232,752	971,975	980,392	983,704
Long-lived assets [Abstract]
Long-lived assets	190,586				192,578				$ 190,586	$ 192,578	$ 159,167
Number of largest individual customers | Customer									5
Net sales by major customer									68.00%	69.00%	66.00%
Litigation charge							$ (10,600)		$ 0	$ 10,650	$ 0
Five Largest Individual Customers [Member]
Long-lived assets [Abstract]
Net sales by major customer									68.00%	69.00%	66.00%
NAPA Auto Parts [Member]
Long-lived assets [Abstract]
Net sales by major customer									19.00%
Advance Auto Parts, Inc. [Member]
Long-lived assets [Abstract]
Net sales by major customer									17.00%
O' Reilly Automotive, Inc. [Member]
Long-lived assets [Abstract]
Net sales by major customer									19.00%
AutoZone, Inc [Member]
Long-lived assets [Abstract]
Net sales by major customer									11.00%
United States [Member]
Revenues [Abstract]
Revenues									$ 881,206	$ 884,701	$ 895,648
Long-lived assets [Abstract]
Long-lived assets	155,438				158,350				155,438	158,350	135,834
Canada [Member]
Revenues [Abstract]
Revenues									48,072	51,526	46,133
Long-lived assets [Abstract]
Long-lived assets	1,190				1,546				1,190	1,546	1,526
Europe [Member]
Revenues [Abstract]
Revenues									16,305	18,061	15,413
Long-lived assets [Abstract]
Long-lived assets	12,324				11,725				12,324	11,725	11,310
Other Foreign [Member]
Revenues [Abstract]
Revenues									26,392	26,104	26,510
Long-lived assets [Abstract]
Long-lived assets	21,634				20,957				21,634	20,957	10,497
Intersegment Eliminations [Member]
Financial information for reportable segment [Abstract]
Net sales									0	0	0
Engine Management [Member] | Reportable Segments [Member]
Financial information for reportable segment [Abstract]
Net sales									698,021	709,263	711,245
Depreciation and amortization									12,256	12,425	13,235
Operating income (loss)									88,007	103,861	96,335
Investment in equity affiliates	6,430				6,368				6,430	6,368	6,308
Capital expenditures									14,574	11,182	8,628
Total assets	413,102				409,275				413,102	409,275	384,712
Reconciliation of segment operating income to net earnings [Abstract]
Operating income									88,007	103,861	96,335
Engine Management [Member] | Intersegment Eliminations [Member]
Financial information for reportable segment [Abstract]
Net sales									20,178	23,633	25,720
Temperature Control [Member] | Reportable Segments [Member]
Financial information for reportable segment [Abstract]
Net sales									264,478	259,065	262,537
Depreciation and amortization									4,329	4,171	3,763
Operating income (loss)									6,382	6,445	9,147
Investment in equity affiliates	14,192				13,636				14,192	13,636	0
Capital expenditures									3,418	2,650	2,682
Total assets	177,201				173,070				177,201	173,070	150,280
Reconciliation of segment operating income to net earnings [Abstract]
Operating income									6,382	6,445	9,147
Temperature Control [Member] | Intersegment Eliminations [Member]
Financial information for reportable segment [Abstract]
Net sales									6,542	6,966	6,329
Other [Member]
Financial information for reportable segment [Abstract]
Net sales									9,476	12,064	9,922
Depreciation and amortization									1,052	699	597
Operating income (loss)									(18,529)	(24,968)	(18,619)
Investment in equity affiliates	0				0				0	0	0
Capital expenditures									55	72	100
Total assets	$ 90,761				$ 91,206				90,761	91,206	80,531
Reconciliation of segment operating income to net earnings [Abstract]
Operating income									(18,529)	(24,968)	(18,619)
Other [Member] | Intersegment Eliminations [Member]
Financial information for reportable segment [Abstract]
Net sales									$ (26,720)	$ (30,599)	$ (32,049)