Condensed Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Net sales	$ 4,100,178	$ 3,899,638	$ 8,005,819	$ 7,617,905
Cost of goods sold	2,860,466	2,734,186	5,610,386	5,347,982
Gross profit	1,239,712	1,165,452	2,395,433	2,269,923
Operating expenses:
Selling, administrative and other expenses	903,343	829,489	1,777,157	1,652,661
Depreciation and amortization	39,232	35,911	77,364	70,565
Total operating expenses	942,575	865,400	1,854,521	1,723,226
Income before income taxes	297,137	300,052	540,912	546,697
Income taxes	107,165	108,683	190,780	197,303
Net income	$ 189,972	$ 191,369	$ 350,132	$ 349,394
Basic net income per common share (usd per share)	$ 1.29	$ 1.28	$ 2.37	$ 2.34
Diluted net income per common share (usd per share)	1.29	1.28	2.36	2.33
Dividends declared per common share (usd per share)	$ 0.675	$ 0.6575	$ 1.350	$ 1.315
Weighted average common shares outstanding (in shares)	147,079	149,241	147,613	149,417
Dilutive effect of stock options and non-vested restricted stock awards (in shares)	571	788	598	761
Weighted average common shares outstanding - assuming dilution (in shares)	147,650	150,029	148,211	150,178
Comprehensive income	$ 218,852	$ 171,723	$ 441,764	$ 397,847