Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net sales	$ 554,814	$ 412,370	$ 1,600,633	$ 1,275,999
Cost of sales	433,594	306,820	1,224,312	945,104
Gross profit	121,220	105,550	376,321	330,895
Selling, general and administrative expenses	73,293	60,412	206,225	170,641
Operating profit	47,927	45,138	170,096	160,254
Interest expense, net	311	396	1,162	1,285
Income before income taxes	47,616	44,742	168,934	158,969
Provision for income taxes	15,478	14,898	53,514	55,597
Net income	$ 32,138	$ 29,844	$ 115,420	$ 103,372
Net income per common share:
Basic (in usd per share)	$ 1.28	$ 1.21	$ 4.62	$ 4.20
Diluted (in usd per share)	$ 1.26	$ 1.19	$ 4.56	$ 4.15
Weighted average common shares outstanding:
Basic (in shares)	25,060	24,724	24,993	24,587
Diluted (in shares)	25,459	25,060	25,332	24,882