Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Operating activities:
Net income	$ 293,612		$ 236,246
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and intangibles	88,230		80,114	[1]
Amortization of debt discount and issuance costs	837		692	[1]
Write-off of asset-based revolving credit facility debt issuance costs	0		21,626	[1]
Excess tax benefit from stock options exercised	(23,692)		(7,381)	[1]
Deferred income taxes	4,375		20,729	[1]
Share-based compensation programs	10,891		10,533	[1]
Other	4,075		5,439	[1]
Changes in operating assets and liabilities:
Accounts receivable	(20,802)		(19,835)	[1]
Inventory	(159,591)		(11,793)	[1]
Accounts payable	420,554		219,546	[1]
Income taxes payable	47,159		27,987	[1]
Other	25,810		(22,435)	[1]
Net cash provided by operating activities	691,458		561,468	[1]
Investing activities:
Purchases of property and equipment	(151,327)		(150,649)	[1]
Proceeds from sale of property and equipment	2,071		621	[1]
Payments received on notes receivable	2,100		3,022	[1]
Other			226	[1]
Net cash used in investing activities	(147,156)		(146,780)	[1]
Financing activities:
Proceeds from borrowings on asset-based revolving credit facility	0		42,400	[1]
Payments on asset-based revolving credit facility	0		(398,400)	[1]
Proceeds from the issuance of long-term debt	0		496,485	[1]
Payment of debt issuance costs	0		(7,385)	[1]
Principal payments on debt and capital leases	(367)		(794)	[1]
Repurchases of common stock	(594,450)		(338,030)	[1]
Excess tax benefit from stock options exercised	23,692		7,381	[1]
Net proceeds from issuance of common stock	32,988		22,726	[1]
Net cash used in financing activities	(538,137)		(175,617)	[1]
Net increase in cash and cash equivalents	6,165		239,071	[1]
Cash and cash equivalents at beginning of period	361,552	[2]	29,721	[1]
Cash and cash equivalents at end of period	367,717		268,792	[1]
Supplemental disclosures of cash flow information:
Income taxes paid	125,575		92,781	[1]
Interest paid, net of capitalized interest	$ 17,718		$ 1,449	[1]

[1] Certain prior period amounts have been reclassified to conform to current period presentation.

[2] The balance sheet at December 31, 2011, has been derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.