Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
Income Statement [Abstract]
Net sales	$ 198,721	$ 196,187	$ 387,195	$ 379,699
Cost of goods sold	122,151	123,226	237,732	235,096
Gross profit	76,570	72,961	149,463	144,603
Selling, general and administrative expenses	39,675	36,261	78,916	70,956
Income from operations	36,895	36,700	70,547	73,647
Interest expense, net	52	63	104	102
Income before income taxes	36,843	36,637	70,443	73,545
Provision for income taxes	13,700	13,393	25,961	26,750
Net income	$ 23,143	$ 23,244	$ 44,482	$ 46,795
Earnings Per Share:
Basic	$ 0.65	$ 0.64	$ 1.25	$ 1.29
Diluted	$ 0.65	$ 0.64	$ 1.25	$ 1.28
Weighted Average Shares Outstanding:
Basic	35,548	36,315	35,545	36,344
Diluted	35,614	36,471	35,629	36,514