CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows From Operating Activities:
Net income (loss)	$ 385,321	$ 390,075
Adjustments to reconcile net income (loss) to net cash flows from operating activities:
Depreciation and amortization	192,972	204,630
Realized and unrealized losses (gains) on investments	36,722	(2,272)
Non-cash, stock-based compensation	9,060	6,774
Deferred tax expense (benefit)	92,064	150,006
Other, net	(32,426)	6,752
Changes in current assets and current liabilities, net	67,838	180,802
Net cash flows from operating activities	751,551	936,767
Cash Flows From Investing Activities:
Purchases of marketable investment securities	(9,253)	(58,876)
Sales and maturities of marketable investment securities	313,567	78,703
Purchases of property and equipment	(70,521)	(114,899)
Capitalized interest related to FCC authorizations (Note 2)	(294,003)	(282,597)
Purchases of strategic investments		(90,921)
Other, net	3,613	13,564
Net cash flows from investing activities	(56,597)	(455,026)
Cash Flows From Financing Activities:
Proceeds from issuance of convertible notes (Note 8)		1,000,000
Redemption and repurchases of senior notes	(56,473)
Repayment of long-term debt and capital lease obligations	(10,458)	(9,162)
Payments made to parent of transferred businesses		(7,098)
Net proceeds from Class A common stock options exercised and stock issued under the Employee Stock Purchase Plan	7,991	6,374
Debt issuance costs		(6,158)
Other, net	(159)
Net cash flows from financing activities	(59,099)	983,956
Net increase (decrease) in cash, cash equivalents, restricted cash and cash equivalents	635,855	1,465,697
Cash, cash equivalents, restricted cash and cash equivalents, beginning of period (Note 5)	1,479,901	5,325,184
Cash, cash equivalents, restricted cash and cash equivalents, end of period (Note 5)	$ 2,115,756	$ 6,790,881