CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net sales	$ 229,265	$ 198,810
Cost of sales	139,766	133,180
Gross margin	89,499	65,630
Selling, general and administrative expenses	42,413	40,330
Research and development expenses	7,172	7,805
Restructuring and impairment charges	1,506	0
Other operating (income) expense, net	1,215	20
Operating income	37,193	17,475
Equity income in unconsolidated joint ventures	2,181	1,218
Other income (expense), net	2,968	(786)
Interest expense, net	(607)	(1,207)
Income before income tax expense	41,735	16,700
Income tax expense	10,517	3,441
Net income	$ 31,218	$ 13,259
Basic earnings per share (in dollars per share)	$ 1.67	$ 0.71
Diluted earnings per share (in dollars per share)	$ 1.66	$ 0.71
Shares used in computing:
Basic earnings per share (in shares)	18,712	18,669
Diluted earnings per share (in shares)	18,774	18,691