Industry Segment and Geographic Data, Operating Income to Earnings (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Reconciliation of segment operating income to net earnings [Abstract]
Operating income										$ 94,495		$ 81,268		$ 97,521
Other non-operating income (expense), net										2,587		(411)		1,250
Interest expense										5,286		4,026		2,329
Earnings from continuing operations before taxes										91,796		76,831		96,442
Income tax expense										22,745		19,977		52,812
Earnings from continuing operations		$ 12,738	$ 22,654	$ 20,555	$ 13,104	$ 12,157	$ 19,273	$ 16,827	$ 8,597	69,051		56,854		43,630
Discontinued operations, net of tax		(1,220)	(7,903)	(1,123)	(888)	(8,837)	(3,524)	(882)	(608)	(11,134)		(13,851)		(5,654)
Net earnings		11,518	14,751	19,432	12,216	3,320	15,749	15,945	7,989	57,917		43,003		37,976
Revenues [Abstract]
Revenues		241,252	$ 307,723	$ 305,172	$ 283,766	246,970	$ 296,619	$ 286,636	$ 261,826	1,137,913	[1],[2]	1,092,051	[1],[2]	1,116,143	[1],[2],[3],[4]
Long-lived assets [Abstract]
Long-lived assets	[5]	326,025				254,574				326,025		254,574		259,056
United States [Member]
Revenues [Abstract]
Revenues	[1]									1,023,903		976,030		1,001,003	[4]
Long-lived assets [Abstract]
Long-lived assets	[5]	253,384				198,494				253,384		198,494		202,875
Canada [Member]
Revenues [Abstract]
Revenues	[1]									50,158		57,460		52,005	[4]
Long-lived assets [Abstract]
Long-lived assets	[5]	4,659				2,718				4,659		2,718		2,017
Mexico [Member]
Revenues [Abstract]
Revenues	[1]									20,035		20,214		24,521	[4]
Long-lived assets [Abstract]
Long-lived assets	[5]	12,036				4,012				12,036		4,012		4,449
Europe [Member]
Revenues [Abstract]
Revenues	[1]									13,875		13,684		14,088	[4]
Long-lived assets [Abstract]
Long-lived assets	[5]	17,004				16,880				17,004		16,880		18,530
Other Foreign [Member]
Revenues [Abstract]
Revenues	[1]									29,942		24,663		24,526	[4]
Long-lived assets [Abstract]
Long-lived assets	[5]	$ 38,942				$ 32,470				$ 38,942		$ 32,470		$ 31,185

[1] Revenues are attributed to countries based upon the location of the customer.

[2] Segment net sales include intersegment sales in our Engine Management and Temperature Control segments.

[3] Net sales and intersegment sales for 2017 have not been restated and are reported under accounting standards in effect in the period presented, as we adopted ASU 2014-09, Revenue from Contracts with Customers, on January 1, 2018 using the modified retrospective method.

[4] Revenues for 2017 have not been restated and are reported under accounting standards in effect in the period presented, as we adopted ASU 2014-09, Revenue from Contracts with Customers, on January 1, 2018 using the modified retrospective method.

[5] Long-lived assets are attributed to countries based upon the location of the assets.