Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales	$ 629,068	$ 684,455	$ 1,221,240	$ 1,334,947
Cost of sales	480,415	533,999	939,993	1,043,758
Gross profit	148,653	150,456	281,247	291,189
Selling, general and administrative expenses	82,996	86,368	167,835	167,281
Operating profit	65,657	64,088	113,412	123,908
Interest expense, net	2,099	1,660	4,606	2,761
Income before income taxes	63,558	62,428	108,806	121,147
Provision for income taxes	16,031	15,204	26,913	26,587
Net income	$ 47,527	$ 47,224	$ 81,893	$ 94,560
Net income per common share:
Basic (in usd per share)	$ 1.90	$ 1.87	$ 3.28	$ 3.75
Diluted (in usd per share)	$ 1.89	$ 1.86	$ 3.28	$ 3.70
Weighted average common shares outstanding:
Basic (in shares)	25,024	25,233	24,963	25,195
Diluted (in shares)	25,091	25,454	25,005	25,527