Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 16,308,801	$ 15,339,713	$ 15,280,044
Cost of goods sold	11,402,403	10,740,106	10,724,192
Gross margin	4,906,398	4,599,607	4,555,852
Operating expenses:
Selling, administrative, and other expenses	3,705,136	3,370,833	3,277,390
Depreciation and amortization	167,691	147,487	141,675
Provision for doubtful accounts	13,932	11,515	12,373
Total operating expenses	3,886,759	3,529,835	3,431,438
Non-operating expenses (income) :
Interest expense	41,486	21,084	21,662
Other	(31,115)	(25,652)	(20,929)
Total non-operating expenses (income)	10,371	(4,568)	733
Income before income taxes	1,009,268	1,074,340	1,123,681
Income taxes	$ 392,511	$ 387,100	$ 418,009
Basic net income per common share (in dollars per share)	$ 4.19	$ 4.61	$ 4.65
Diluted net income per common share (in dollars per share)	$ 4.18	$ 4.59	$ 4.63
Weighted average common shares outstanding (in shares)	147,140	149,051	151,667
Dilutive effect of stock options and nonvested restricted stock awards (in shares)	561	753	829
Weighted average common shares outstanding — assuming dilution (in shares)	147,701	149,804	152,496
Net income	$ 616,757	$ 687,240	$ 705,672
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	137,694	(8,957)	(207,986)
Net investment hedge, net of income taxes of 2017 — $9,711	(17,388)	0	0
Pension and postretirement benefit adjustments, net of income taxes of 2017 — ($20,539); 2016 — $50,144; 2015 — $5,335	40,123	(73,446)	(2,421)
Other comprehensive income (loss), net of tax	160,429	(82,403)	(210,407)
Comprehensive income	$ 777,186	$ 604,837	$ 495,265