Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016		Mar. 31, 2015
Operating activities:
Net income	$ 255,374		$ 212,864
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and intangibles	52,778		54,950
Amortization of debt discount and issuance costs	546		525
Excess tax benefit from share-based compensation	(14,762)		(21,188)
Deferred income taxes	(3,322)		(4,441)
Share-based compensation programs	5,178		5,890
Other	1,481		1,355
Changes in operating assets and liabilities:
Accounts receivable	(19,206)		(19,867)
Inventory	(70,745)		26,807
Accounts payable	174,378		53,582
Income taxes payable	127,638		117,221
Other	(21,183)		(21,673)
Net cash provided by operating activities	488,155		406,025
Investing activities:
Purchases of property and equipment	(103,974)		(91,140)
Proceeds from sale of property and equipment	864		658
Payments received on notes receivable	1,047		935
Net cash used in investing activities	(102,063)		(89,547)
Financing activities:
Proceeds from the issuance of long-term debt	499,160		0
Payments of debt issuance costs	(3,725)		0
Principal payments on capital leases	0		(19)
Repurchases of common stock	(312,656)		(134,813)
Excess tax benefit from share-based compensation	14,762		21,188
Net proceeds from issuance of common stock	16,074		20,252
Net cash provided by (used in) financing activities	213,615		(93,392)
Net increase in cash and cash equivalents	599,707		223,086
Cash and cash equivalents at beginning of the period	116,301	[1]	250,560
Cash and cash equivalents at end of the period	716,008		473,646
Supplemental disclosures of cash flow information:
Income taxes paid	23,765		8,675
Interest paid, net of capitalized interest	$ 23,063		$ 23,435

[1] The balance sheet at December 31, 2015, has been derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by United States generally accepted accounting principles for complete financial statements.