Condensed Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 755,569,000	$ 482,850,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	193,106,000	196,157,000
(Gain) Loss on disposal of property and equipment	(179,000)	255,000
Provision for deferred income taxes	9,193,000	(25,155,000)
Other, net	22,915,000	16,668,000
Changes in operating assets and liabilities, net	(107,989,000)	15,683,000
Net cash provided by operating activities	872,615,000	686,458,000
Cash flows from investing activities:
Purchase of property and equipment	(384,688,000)	(166,459,000)
Proceeds from sale of property and equipment	18,635,000	3,411,000
Purchase of short-term investments	(254,832,000)	(205,301,000)
Proceeds from maturities of short-term investments	360,203,000
Other investing, net	(500,000)	(100,000)
Net cash used in investing activities	(261,182,000)	(368,449,000)
Cash flows from financing activities:
Proceeds from issuance of long-term debt		99,923,000
Payments for share repurchases	(536,465,000)	(306,791,000)
Forward contract for accelerated share repurchases	(62,500,000)	(37,500,000)
Dividends paid	(69,387,000)	(53,471,000)
Other financing activities, net	(4,750,000)	(3,345,000)
Net cash used in financing activities	(673,102,000)	(301,184,000)
(Decrease) Increase in cash and cash equivalents	(61,669,000)	16,825,000
Cash and cash equivalents at beginning of period	401,430,000	403,571,000
Cash and cash equivalents at end of period	$ 339,761,000	$ 420,396,000