Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net income	$ 1,752,302	$ 1,391,042	$ 1,324,487
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and intangibles	314,635	270,875	258,937
Amortization of debt discount and issuance costs	4,580	3,916	3,470
Deferred income taxes	12,381	21,158	20,160
Share-based compensation programs	22,747	21,921	20,176
Other	4,686	7,529	9,895
Changes in operating assets and liabilities:
Accounts receivable	(20,515)	(15,577)	18,138
Inventory	(198,864)	(239,912)	(163,367)
Accounts payable	580,608	213,423	177,676
Income taxes payable	197,739	(20,139)	22,903
Accrued payroll	(11,941)	14,296	9,373
Accrued benefits and withholdings	189,332	16,868	28,022
Other	(11,087)	23,079	(2,315)
Net cash provided by operating activities	2,836,603	1,708,479	1,727,555
Investing activities:
Purchases of property and equipment	(465,579)	(628,057)	(504,268)
Proceeds from sale of property and equipment	15,770	7,118	4,784
Investment in tax credit equity investments	(164,111)	(33,781)	0
Other, including acquisitions, net of cash acquired	(975)	(142,026)	(34,818)
Net cash used in investing activities	(614,895)	(796,746)	(534,302)
Financing activities:
Proceeds from borrowings on revolving credit facility	1,162,000	2,708,000	2,414,000
Payments on revolving credit facility	(1,423,000)	(2,734,000)	(2,473,000)
Proceeds from the issuance of long-term debt	997,515	499,955	498,660
Principal payments on long-term debt	(500,000)	0	0
Payment of debt issuance costs	(7,929)	(3,990)	(3,923)
Repurchases of common stock	(2,087,194)	(1,432,791)	(1,714,013)
Net proceeds from issuance of common stock	62,284	60,206	72,146
Other	(253)	(191)	(2,156)
Net cash used in financing activities	(1,796,577)	(902,811)	(1,208,286)
Effect of exchange rate changes on cash	103	169	0
Net increase (decrease) in cash and cash equivalents	425,234	9,091	(15,033)
Cash and cash equivalents at beginning of the period	40,406	31,315	46,348
Cash and cash equivalents at end of the period	465,640	40,406	31,315
Supplemental disclosures of cash flow information:
Income taxes paid	305,087	394,931	311,376
Interest paid, net of capitalized interest	$ 159,717	$ 134,634	$ 117,938