Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 2,473	$ 2,390
Restructuring charges	$ 1,393	$ 215	986	131
Cash payments			2,614	1,285
Restructuring reserve, ending balance	845	1,236	845	1,236
Severance
Restructuring Reserve [Roll Forward]
Restructuring charges			109	104
Closure costs
Restructuring Reserve [Roll Forward]
Restructuring charges			877	27
2016 Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			1,300
Restructuring charges	1,378		2,152
Cash payments			3,242
Restructuring reserve, ending balance	210		210
2016 Plan | Severance
Restructuring Reserve [Roll Forward]
Restructuring charges			116
2016 Plan | Closure costs
Restructuring Reserve [Roll Forward]
Restructuring charges			2,036
2015 Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			282	774
Restructuring charges	16		(34)
Cash payments			248	607
Restructuring reserve, ending balance	0	298	0	298
2015 Plan | Severance
Restructuring Reserve [Roll Forward]
Restructuring charges			(7)	104
2015 Plan | Closure costs
Restructuring Reserve [Roll Forward]
Restructuring charges			(27)	27
2014 Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			426	442
Restructuring charges	(1)		(1,132)
Cash payments			(1,120)	16
Restructuring reserve, ending balance	414	426	414	426
2014 Plan | Severance
Restructuring Reserve [Roll Forward]
Restructuring charges			0	0
2014 Plan | Closure costs
Restructuring Reserve [Roll Forward]
Restructuring charges			(1,132)	0
2013 Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance				316
Cash payments				316
Restructuring reserve, ending balance		0		0
2013 Plan | Severance
Restructuring Reserve [Roll Forward]
Restructuring charges				0
2013 Plan | Closure costs
Restructuring Reserve [Roll Forward]
Restructuring charges				0
2012 and Prior Plans
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			465	858
Cash payments			244	346
Restructuring reserve, ending balance	$ 221	$ 512	221	512
2012 and Prior Plans | Severance
Restructuring Reserve [Roll Forward]
Restructuring charges			0	0
2012 and Prior Plans | Closure costs
Restructuring Reserve [Roll Forward]
Restructuring charges			$ 0	$ 0