Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 247,954	$ 224,615	$ 713,363	$ 675,502
Cost of goods sold	152,957	136,489	437,029	407,781
Gross profit	94,997	88,126	276,334	267,721
Selling, general and administrative expenses	51,264	45,336	149,828	134,890
Income from operations	43,733	42,790	126,506	132,831
Other income, net	61	168	286	472
Income before income taxes	43,794	42,958	126,792	133,303
Provision for income taxes	9,777	15,950	27,789	48,671
Net income	$ 34,017	$ 27,008	$ 99,003	$ 84,632
Earnings Per Share:
Basic	$ 1.03	$ 0.80	$ 2.98	$ 2.48
Diluted	$ 1.03	$ 0.80	$ 2.98	$ 2.47
Weighted Average Shares Outstanding:
Basic	32,985	33,822	33,177	34,111
Diluted	33,095	33,909	33,267	34,202