Consolidated Statements of Net Income - USD ($) shares in Thousands	12 Months Ended
	Jan. 02, 2016	Dec. 27, 2014	Dec. 28, 2013
Net sales	$ 867,864,000	$ 851,995,000	$ 757,853,000
Cost of sales	537,365,000	527,567,000	461,621,000
Gross profit	330,499,000	324,428,000	296,232,000
Selling, general and administrative expenses	153,714,000	146,975,000	132,657,000
Research and development expenses	30,802,000	$ 31,122,000	$ 24,415,000
Pension settlement expenses	29,928,000
Amortization of intangibles	11,898,000	$ 12,501,000	$ 9,279,000
Total operating expenses	226,342,000	190,598,000	166,351,000
Operating income	104,157,000	133,830,000	129,881,000
Interest expense	$ 4,091,000	$ 4,903,000	2,917,000
Impairment and equity in net loss of unconsolidated affiliate			10,678,000
Foreign exchange (gain) loss	$ (1,465,000)	$ 3,925,000	(3,303,000)
Other expense (income), net	(5,417,000)	(6,644,000)	(4,646,000)
Income before income taxes	106,948,000	131,646,000	124,236,000
Income taxes	24,482,000	32,228,000	35,451,000
Net income	$ 82,466,000	$ 99,418,000	$ 88,784,000
Income per share:
Basic (in dollars per share)	$ 3.65	$ 4.41	$ 3.98
Diluted (in dollars per share)	$ 3.63	$ 4.37	$ 3.94
Weighted-average shares and equivalent shares outstanding:
Weighted-average shares (in shares)	22,565	22,543	22,315
Adjusted for weighted-average shares & assumed conversions (in shares)	22,719	22,727	22,537