Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2016	Jul. 03, 2015	Jul. 01, 2016	Jul. 03, 2015
Income Statement [Abstract]
Net sales	$ 470,642	$ 446,324	$ 921,840	$ 889,106
Cost of sales	326,876	314,372	643,644	629,243
Gross profit	143,766	131,952	278,196	259,863
Selling, general and administrative expenses	113,905	101,953	230,013	207,507
Net (gain) / loss on sale of assets	14	(432)	(14)	(405)
Operating income	29,847	30,431	48,197	52,761
Interest expense, net	3,988	3,222	7,795	6,549
Other expense (income), net	489	(1)	575	(65)
Earnings before income taxes	25,370	27,210	39,827	46,277
Income tax expense	8,875	5,519	13,555	11,837
Net earnings	$ 16,495	$ 21,691	$ 26,272	$ 34,440
Earnings per share:
Basic earnings per share (in usd per share)	$ 0.61	$ 0.80	$ 0.97	$ 1.27
Diluted earnings per share (in usd per share)	$ 0.59	$ 0.77	$ 0.94	$ 1.23
Average shares outstanding:
Basic (in shares)	27,101	27,240	27,080	27,214
Diluted (in shares)	27,944	28,098	27,875	27,988
Dividends declared per share (in usd per share)	$ 0.18	$ 0.18	$ 0.36	$ 0.36