Condensed Consolidated Statements of Operations- Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 03, 2020	Mar. 29, 2019
Income Statement [Abstract]
Sales	$ 328,426	$ 314,676
Cost of sales	231,724	226,066
Gross profit	96,702	88,610
Operating expenses:
Selling, general and administrative expenses	36,457	34,956
Research, development and engineering costs	13,241	11,595
Other operating expenses	2,928	2,890
Total operating expenses	52,626	49,441
Operating income	44,076	39,169
Interest expense	10,361	13,830
(Gain) loss on equity investments, net	(1,925)	41
Other (income) loss, net	(999)	166
Income from continuing operations before taxes	36,639	25,132
Provision for income taxes	5,539	3,766
Income from continuing operations	31,100	21,366
Discontinued operations:
Income from discontinued operations before taxes	0	386
Provision for income taxes	0	83
Income from discontinued operations	0	303
Net income	$ 31,100	$ 21,669
Basic earnings per share:
Income from continuing operations (in dollars per share)	$ 0.95	$ 0.66
Loss from discontinued operations (in dollars per share)	0	0.01
Basic (in dollars per share)	0.95	0.67
Diluted earnings per share:
Income from continuing operations (in dollars per share)	0.94	0.65
Loss from discontinued operations (in dollars per share)	0	0.01
Diluted (in dollars per share)	$ 0.94	$ 0.66
Weighted average shares outstanding:
Basic (in shares)	32,807	32,536
Diluted (in shares)	33,117	32,980