Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements of Income [Abstract]
Net sales	$ 12,458,877	$ 11,207,589	$ 10,057,512
Cost of goods sold	8,852,837	7,954,645	7,047,750
Gross margin	3,606,040	3,252,944	3,009,762
Operating expenses:
Selling, administrative and other expenses	2,594,372	2,366,667	2,219,935
Depreciation and amortization	88,936	89,332	90,411
Provision for doubtful accounts	13,248	10,597	28,463
Total operating expenses	2,696,556	2,466,596	2,338,809
Non-operating expenses (income):
Interest expense	27,036	28,061	27,885
Other	(8,358)	(3,496)	(1,097)
Total non-operating expense	18,678	24,565	26,788
Income before income taxes	890,806	761,783	644,165
Income taxes	325,690	286,272	244,590
Net income	$ 565,116	$ 475,511	$ 399,575
Basic net income per common share	$ 3.61	$ 3.01	$ 2.51
Diluted net income per common share	$ 3.58	$ 3.00	$ 2.50
Weighted average common shares outstanding	156,656	158,032	159,410
Dilutive effect of stock options and nonvested restricted stock awards	1,004	429	297
Weighted average common shares outstanding - assuming dilution	157,660	158,461	159,707