Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 586,221	$ 604,244	$ 1,807,461	$ 1,939,191
Cost of sales	450,748	478,343	1,390,741	1,522,101
Gross profit	135,473	125,901	416,720	417,090
Selling, general and administrative expenses	86,320	80,548	254,155	247,829
Operating profit	49,153	45,353	162,565	169,261
Interest expense, net	1,900	1,720	6,506	4,481
Income before income taxes	47,253	43,633	156,059	164,780
Provision for income taxes	11,444	9,821	38,357	36,408
Net income	$ 35,809	$ 33,812	$ 117,702	$ 128,372
Net income per common share:
Basic (in usd per share)	$ 1.43	$ 1.34	$ 4.71	$ 5.09
Diluted (in usd per share)	$ 1.42	$ 1.33	$ 4.70	$ 5.03
Weighted average common shares outstanding:
Basic (in shares)	25,031	25,235	24,984	25,208
Diluted (in shares)	25,156	25,504	25,053	25,509