Consolidated Statements of Income (Unaudited) - 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	$ 1,121,328	$ 1,057,804	$ 1,718,784	$ 1,643,704
Cost of sales	791,014	749,149	1,213,839	1,168,976
Gross profit	330,314	308,655	504,945	474,728
Selling and administrative expenses	157,791	146,613	294,036	279,145
Operating income	172,523	162,042	210,909	195,583
Interest and other non-operating expenses, net	6,424	5,991	13,040	9,518
Income before income taxes and equity earnings	166,099	156,051	197,869	186,065
Provision for income taxes	34,778	39,062	33,976	37,783
Equity earnings in unconsolidated investments, net	69	60	134	106
Net income	$ 131,390	$ 117,049	$ 164,027	$ 148,388
Earnings per share:
Basic (in dollars per share)	$ 3.30	$ 2.89	$ 4.14	$ 3.67
Diluted (in dollars per share)	$ 3.22	$ 2.80	$ 4.02	$ 3.55
Weighted average shares outstanding: [Abstract]
Basic (in shares)	39,827	40,453	39,654	40,413
Diluted (in shares)	40,848	41,814	40,773	41,840
Cash dividends declared per common share	$ 0.55	$ 0.45	$ 1.00	$ 0.82