Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Sales	$ 2,282,681	$ 2,156,259
Cost of goods sold, including warehouse and distribution expenses	1,081,423	1,025,112
Gross profit	1,201,258	1,131,147
Selling, general and administrative expenses	778,412	727,990
Operating income	422,846	403,157
Other income (expense):
Interest expense	(28,217)	(19,404)
Interest income	572	706
Other, net	205	765
Total other expense	(27,440)	(17,933)
Income before income taxes	395,406	385,224
Provision for income taxes	90,500	120,290
Net income	$ 304,906	$ 264,934
Earnings per share-basic:
Earnings per share - basic	$ 3.65	$ 2.88
Weighted-average common shares outstanding - basic	83,530	92,001
Earnings per share-assuming dilution:
Earnings per share - assuming dilution	$ 3.61	$ 2.83
Weighted-average common shares outstanding - assuming dilution	84,523	93,495