Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018		Mar. 31, 2017
Operating activities:
Net income	$ 304,906		$ 264,934
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and intangibles	69,920		57,008
Amortization of debt discount and issuance costs	795		642
Deferred income taxes	4,370		2,611
Share-based compensation programs	5,176		5,428
Other	2,244		1,810
Changes in operating assets and liabilities:
Accounts receivable	(10,421)		219
Inventory	(42,643)		(93,167)
Accounts payable	32,756		51,230
Income taxes payable	79,380		116,009
Other	(14,206)		(30,024)
Net cash provided by operating activities	432,277		376,700
Investing activities:
Purchases of property and equipment	(114,843)		(110,632)
Proceeds from sale of property and equipment	752		245
Other	(375)		(636)
Net cash used in investing activities	(114,466)		(111,023)
Financing activities:
Proceeds from borrowings on revolving credit facility	755,000		482,000
Payments on revolving credit facility	(541,000)		(392,000)
Repurchases of common stock	(549,450)		(490,330)
Net proceeds from issuance of common stock	11,972		15,750
Other	(2,156)		(156)
Net cash used in financing activities	(325,634)		(384,736)
Net decrease in cash and cash equivalents	(7,823)		(119,059)
Cash and cash equivalents at beginning of the period	46,348	[1]	146,598
Cash and cash equivalents at end of the period	38,525		27,539
Supplemental disclosures of cash flow information:
Income taxes paid	7,939		0
Interest paid, net of capitalized interest	$ 48,763		$ 31,954

[1] The balance sheet at December 31, 2017, 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.