Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Income Statement [Abstract]
Net sales	$ 210,928	$ 197,796	$ 598,123	$ 577,495
Cost of goods sold	130,134	121,915	367,866	357,011
Gross profit	80,794	75,881	230,257	220,484
Selling, general and administrative expenses	39,554	37,405	118,470	108,361
Income from operations	41,240	38,476	111,787	112,123
Interest expense, net	48	58	152	160
Income before income taxes	41,192	38,418	111,635	111,963
Provision for income taxes	15,132	13,882	41,093	40,632
Net income	$ 26,060	$ 24,536	$ 70,542	$ 71,331
Earnings Per Share:
Basic	$ 0.73	$ 0.68	$ 1.99	$ 1.97
Diluted	$ 0.73	$ 0.68	$ 1.98	$ 1.96
Weighted Average Shares Outstanding:
Basic	35,514	35,898	35,535	36,217
Diluted	35,575	36,024	35,611	36,372