Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Operating activities:
Net income	$ 931,216		$ 778,182		$ 670,292
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and intangibles	210,256		194,205		183,180
Amortization of debt discount and issuance costs	2,106		2,086		2,054
Excess tax benefit from share-based compensation	(63,078)		(49,150)		(30,811)
Deferred income taxes	(22,650)		1,487		1,919
Share-based compensation programs	21,899		23,095		21,722
Other	6,839		5,592		7,405
Changes in operating assets and liabilities:
Accounts receivable	(23,858)		(19,271)		(16,937)
Inventory	(76,226)		(179,742)		(96,876)
Accounts payable	191,064		360,646		127,178
Income taxes payable	81,617		32,158		24,777
Accrued payroll	(19,341)		12,923		5,400
Accrued benefits and withholdings	17,970		28,899		2,355
Other	23,662		(680)		6,368
Net cash provided by operating activities	1,281,476		1,190,430		908,026
Investing activities:
Purchases of property and equipment	(414,020)		(429,987)		(395,881)
Proceeds from sale of property and equipment	2,758		2,880		1,731
Payments received on notes receivable	4,074		3,705		5,396
Net cash used in investing activities	(407,188)		(423,402)		(388,754)
Financing activities:
Proceeds from the issuance of long-term debt	0		0		299,976
Payment of debt issuance costs	0		0		(2,967)
Principal payments on capital leases	(25)		(72)		(224)
Repurchases of common stock	(1,136,213)		(866,484)		(933,028)
Excess tax benefit from share-based compensation	63,078		49,150		30,811
Net proceeds from issuance of common stock	64,613		69,620		69,350
Net cash used in financing activities	(1,008,547)		(747,786)		(536,082)
Net (decrease) increase in cash and cash equivalents	(134,259)		19,242		(16,810)
Cash and cash equivalents at beginning of the year	250,560	[1]	231,318		248,128
Cash and cash equivalents at end of the year	116,301		250,560	[1]	231,318
Supplemental disclosures of cash flow information:
Income taxes paid	485,824		416,458		362,596
Interest paid, net of capitalized interest	$ 55,061		$ 51,203		$ 46,760

[1] Certain prior period amounts have been reclassified to conform to current period presentation. See Note 1 "Summary of Significant Accounting Policies" to the Consolidated Financial Statements for more information.