CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net sales	[1]	$ 1,128,588		$ 1,137,913		$ 1,092,051
Cost of sales		791,933		806,113		779,264
Gross profit		336,655		331,800		312,787
Selling, general and administrative expenses		224,670		234,715		231,336
Intangible asset impairment		2,600		0		0
Restructuring and integration expenses		464	[2]	2,585	[2]	4,510
Other income (expense), net		(26)		(5)		4,327
Operating income		108,895		94,495		81,268
Other non-operating income (expense), net		812		2,587		(411)
Interest expense		2,328		5,286		4,026
Earnings from continuing operations before taxes		107,379		91,796		76,831
Provision for income taxes		26,962		22,745		19,977
Earnings from continuing operations		80,417		69,051		56,854
Loss from discontinued operations, net of income tax benefit of $8,089, $3,912 and $4,866		(23,024)		(11,134)		(13,851)
Net earnings		$ 57,393		$ 57,917		$ 43,003
Net earnings per common share - Basic:
Earnings from continuing operations (in dollars per share)		$ 3.59		$ 3.09		$ 2.53
Discontinued operations (in dollars per share)		(1.02)		(0.50)		(0.62)
Net earnings per common share - Basic (in dollars per share)		2.57		2.59		1.91
Net earnings per common share - Diluted:
Earnings from continuing operations (in dollars per share)		3.52		3.03		2.48
Discontinued operations (in dollars per share)		(1.01)		(0.49)		(0.60)
Net earnings per common share - Diluted (in dollars per share)		2.51		2.54		1.88
Dividends declared per share (in dollars per share)		$ 0.50		$ 0.92		$ 0.84
Average number of common shares (in shares)		22,374,123		22,378,414		22,456,480
Average number of common shares and dilutive common shares (in shares)		22,825,885		22,818,451		22,931,723

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

[2] Included in restructuring and integration costs in 2020 and 2019 is a $0.3 million and $0.4 million increase, respectively, in environmental cleanup costs related to ongoing monitoring and remediation in connection with the prior closure of our manufacturing operations at our Long Island City, New York location.  The environmental liability has been reclassed to accrued liabilities as of December 31, 2020 and 2019, respectively.