Interim Financial Statements (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from Related Parties		$ 189,490	$ 210,367
Deferred tax assets		532,268		$ 506,291
Total assets		9,372,696		8,764,286
Accrued Liabilities and Other Liabilities		666,216		637,162
Deferred Revenue From Related Party Current		231,447		177,746
Deferred Revenue, Current		160,466		142,392
Liabilities, Current		1,265,740		1,135,483
Deferred Revenue From Related Party Noncurrent		(406,778)		(379,936)
Deferred Revenue, Noncurrent		257,967		249,263
Liabilities		2,805,052		2,620,208
Retained earnings		3,287,767		2,946,733
Total stockholders' equity		6,567,644		6,144,078
Liabilities and Equity		9,372,696		$ 8,764,286
Other revenue		86,158	56,440
Revenues		1,511,485	1,318,991
Operating Income (Loss)		567,231	430,542
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		585,398	432,289
Income Tax Expense (Benefit)		(107,418)	(183,358)
Net Income (Loss) Attributable to Parent		477,980	$ 248,931
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ 143,400
Accounting Standards Update 2016-01 [Member] | Unrestricted [Member] | Equity Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	(6,600)
Reclassification from AOCI to Retained Earnings	6,600
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
(Decrease) increase in deferred revenue	$ 143,400
Adjustments | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from Related Parties		(8,407)
Deferred tax assets		(18,206)
Total assets		(18,206)
Accrued Liabilities and Other Liabilities		(1,513)
Deferred Revenue From Related Party Current		(33,632)
Deferred Revenue, Current		(69,241)
Liabilities, Current		(104,386)
Deferred Revenue From Related Party Noncurrent		51,604
Deferred Revenue, Noncurrent		18,277
Liabilities		(137,713)
Retained earnings		119,507
Total stockholders' equity		119,507
Liabilities and Equity		(18,206)
Other revenue		(17,310)
Revenues		(25,717)
Operating Income (Loss)		(25,717)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		(25,717)
Income Tax Expense (Benefit)		1,789
Net Income (Loss) Attributable to Parent		(23,928)
Balance Without Adoption of ASC 606 | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue from Related Parties		181,083
Deferred tax assets		514,062
Total assets		9,354,490
Accrued Liabilities and Other Liabilities		664,703
Deferred Revenue From Related Party Current		197,815
Deferred Revenue, Current		91,225
Liabilities, Current		1,161,354
Deferred Revenue From Related Party Noncurrent		(355,174)
Deferred Revenue, Noncurrent		276,244
Liabilities		2,667,339
Retained earnings		3,407,274
Total stockholders' equity		6,687,151
Liabilities and Equity		9,354,490
Other revenue		68,848
Revenues		1,485,768
Operating Income (Loss)		541,514
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		559,681
Income Tax Expense (Benefit)		(105,629)
Net Income (Loss) Attributable to Parent		$ 454,052