Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jun. 25, 2016	Jul. 01, 2017	Jun. 25, 2016
Income Statement [Abstract]
Net sales	$ 229,262	$ 209,573	$ 450,887	$ 417,721
Cost of goods sold	138,410	127,409	271,292	254,963
Gross profit	90,852	82,164	179,595	162,758
Selling, general and administrative expenses	45,853	41,175	89,554	82,838
Income from operations	44,999	40,989	90,041	79,920
Interest income (expense), net	241	(62)	305	(119)
Income before income taxes	45,240	40,927	90,346	79,801
Provision for income taxes	16,803	14,945	32,722	29,148
Net income	$ 28,437	$ 25,982	$ 57,624	$ 50,653
Earnings Per Share:
Basic	$ 0.83	$ 0.75	$ 1.68	$ 1.46
Diluted	$ 0.83	$ 0.75	$ 1.68	$ 1.46
Weighted Average Shares Outstanding:
Basic	34,128	34,546	34,256	34,615
Diluted	34,225	34,626	34,350	34,669