Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Net sales	$ 1,280,846	$ 1,121,328	$ 1,958,134	$ 1,718,784
Cost of sales	907,365	791,014	1,395,024	1,213,839
Gross profit	373,481	330,314	563,110	504,945
Selling and administrative expenses	167,624	157,791	314,721	294,036
Impairment of goodwill and other assets	0	0	6,944	0
Operating income	205,857	172,523	241,445	210,909
Interest and other non-operating expenses, net	2,643	6,424	7,432	13,040
Income before income taxes and equity earnings	203,214	166,099	234,013	197,869
Income tax provision	45,733	34,778	45,708	33,976
Equity earnings in unconsolidated investments, net	74	69	162	134
Net income	$ 157,555	$ 131,390	$ 188,467	$ 164,027
Earnings per share:
Basic (in dollars per share)	$ 3.94	$ 3.30	$ 4.71	$ 4.14
Diluted (in dollars per share)	$ 3.87	$ 3.22	$ 4.62	$ 4.02
Weighted average shares outstanding: [Abstract]
Basic (in shares)	39,973	39,827	40,049	39,654
Diluted (in shares)	40,715	40,848	40,837	40,773
Cash dividends declared per common share	$ 0.58	$ 0.55	$ 1.13	$ 1.00