Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net sales	$ 547,483	$ 440,831	$ 1,045,819	$ 863,629
Cost of sales	416,396	323,927	790,718	638,284
Gross profit	131,087	116,904	255,101	225,345
Selling, general and administrative expenses	68,047	57,516	132,932	110,229
Operating profit	63,040	59,388	122,169	115,116
Interest expense, net	414	413	851	889
Income before income taxes	62,626	58,975	121,318	114,227
Provision for income taxes	22,489	21,406	38,036	40,699
Net income	$ 40,137	$ 37,569	$ 83,282	$ 73,528
Net income per common share:
Basic (in usd per share)	$ 1.61	$ 1.52	$ 3.34	$ 3.00
Diluted (in usd per share)	$ 1.59	$ 1.51	$ 3.29	$ 2.96
Weighted average common shares outstanding:
Basic (in shares)	24,992	24,662	24,959	24,542
Diluted (in shares)	25,305	24,916	25,296	24,822