CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash Flows From Operating Activities:
Net income (loss)	$ 244,153	$ 177,636
Adjustments to reconcile net income (loss) to net cash flows from operating activities:
Depreciation and amortization	135,085	155,115
Realized and unrealized losses (gains) on investments		(2,331)
Non-cash, stock-based compensation	6,953	11,003
Deferred tax expense (benefit)	(13,519)	(23,218)
Allowance for credit losses and allowance for doubtful accounts, respectively	19,526	2,011
Other, net	4,804	(8,546)
Changes in current assets and current liabilities, net	137,511	84,379
Net cash flows from operating activities	534,513	396,049
Cash Flows From Investing Activities:
(Purchases) Sales and maturities of marketable investment securities, net	(60,543)	(33,401)
Purchases of property and equipment	(75,421)	(93,803)
Other, net	2,017	9,425
Net cash flows from investing activities	(133,947)	(117,779)
Cash Flows From Financing Activities:
Redemption and repurchases of senior notes		(22,365)
Advances to/from affiliates	(82,415)
Repayment of long-term debt and finance lease obligations	(11,452)	(6,232)
Other, net		(400)
Net cash flows from financing activities	(93,867)	(28,997)
Net increase (decrease) in cash, cash equivalents, restricted cash and cash equivalents	306,699	249,273
Cash, cash equivalents, restricted cash and cash equivalents, beginning of period (Note 4)	78,103	130,076
Cash, cash equivalents, restricted cash and cash equivalents, end of period (Note 4)	$ 384,802	$ 379,349