CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		123 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018
Cash Flows From Operating Activities:
Net income (loss)	$ 203,808	$ 240,958
Adjustments to reconcile net income (loss) to net cash flows from operating activities:
Depreciation and amortization	178,519	182,028
Realized and unrealized losses (gains) on investments	36,727
Non-cash, stock-based compensation	9,041	6,774
Deferred tax expense (benefit)	(17,710)	(15,793)
Other, net	(32,404)	4,752
Changes in current assets and current liabilities, net	1,548	57,195
Net cash flows from operating activities	379,529	475,914
Cash Flows From Investing Activities:
(Purchases) Sales and maturities of marketable investment securities, net	59,465	2,805
Purchases of property and equipment	(66,715)	(113,584)
Purchases of strategic investments		(90,921)	$ (21,000,000)
Other, net	3,207	10,885
Net cash flows from investing activities	(4,043)	(190,815)
Cash Flows From Financing Activities:
Redemption and repurchases of senior notes	(56,473)
Payments made to parent of transferred businesses		(7,098)
Repayment of long-term debt and capital lease obligations	(9,630)	(8,647)
Other, net	(159)
Net cash flows from financing activities	(66,262)	(15,745)
Net increase (decrease) in cash, cash equivalents, restricted cash and cash equivalents	309,224	269,354
Cash, cash equivalents, restricted cash and cash equivalents, beginning of period (Note 4)	365,066	778,259
Cash, cash equivalents, restricted cash and cash equivalents, end of period (Note 4)	$ 674,290	$ 1,047,613	$ 674,290