Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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
Selected quarterly financial information [Abstract]
Net sales	$ 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]
Gross profit	72,844	92,088	88,905	77,963	71,603	87,306	81,289	72,589	331,800		312,787		326,656
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
Loss from discontinued operations, net of taxes	(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
Net earnings from continuing operations per common share [Abstract]
Basic (in dollars per share)	$ 0.57	$ 1.01	$ 0.92	$ 0.58	$ 0.54	$ 0.86	$ 0.75	$ 0.38	$ 3.09		$ 2.53		$ 1.92
Diluted (in dollars per share)	0.56	1.00	0.90	0.57	0.53	0.84	0.73	0.37	3.03		2.48		1.88
Net earnings per common share [Abstract]
Basic (in dollars per share)	0.51	0.66	0.87	0.54	0.15	0.70	0.71	0.36	2.59		1.91		1.67
Diluted (in dollars per share)	$ 0.50	$ 0.65	$ 0.85	$ 0.53	$ 0.14	$ 0.69	$ 0.69	$ 0.35	$ 2.54		$ 1.88		$ 1.64

[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.