Consolidated Statements of Earnings - Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 29, 2015
Income Statement [Abstract]
Net sales	$ 96,705	$ 98,311
Cost of goods sold	63,237	66,175
Gross Margin	33,468	32,136
Selling, general and administrative expenses	14,872	15,711
Research and development expenses	6,163	5,199
Restructuring and impairment charges	0	738
Operating (loss) earnings	12,433	10,488
Other (expense) income:
Interest expense	(820)	(588)
Interest income	547	788
Other expense	(195)	(1,684)
Total other expense	(468)	(1,484)
Earnings before income taxes	11,965	9,004
Income tax expense	4,102	2,717
Net earnings	$ 7,863	$ 6,287
(Loss) earnings per share:
Basic (in dollars per share)	$ 0.24	$ 0.19
Diluted (in dollars per share)	$ 0.24	$ 0.19
Basic weighted - average common shares outstanding (in shares):	32,632	33,411
Effect of dilutive securities (in shares)	373	524
Diluted weighted - average common shares outstanding (in shares)	33,005	33,935
Cash dividends declared per share (in dollars per share)	$ 0.040	$ 0.040