Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	$ 5,178,187	$ 5,043,786	$ 3,370,097	$ 3,812,041
Cash and cash equivalents
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	5,151,884	5,018,437
Other Current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	2,514	1,863
Non-current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	23,789	23,486
Cash
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	3,126,839	3,127,549
Cash | Cash and cash equivalents
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	3,100,789	3,103,525
Cash | Other Current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	2,514	1,863
Cash | Non-current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	23,536	22,161
Level 1 Securities | Money market funds
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	1,751,348	1,616,237
Level 1 Securities | Money market funds | Cash and cash equivalents
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	1,751,095	1,614,912
Level 1 Securities | Money market funds | Other Current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	0	0
Level 1 Securities | Money market funds | Non-current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	253	1,325
Level 2 Securities | Foreign Time Deposits
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	300,000	300,000
Level 2 Securities | Foreign Time Deposits | Cash and cash equivalents
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	300,000	300,000
Level 2 Securities | Foreign Time Deposits | Other Current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	0	0
Level 2 Securities | Foreign Time Deposits | Non-current Assets
Cash and Cash Equivalents [Line Items]
Cash, cash equivalents, and restricted cash	$ 0	$ 0