Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Cash and cash equivalents and short-term investments	$ 2,700,000	$ 2,900,000
Restricted cash and cash equivalents and restricted short-term investments	1,500,000	1,600,000
Other investments	10,000	0
Cash and Cash Equivalents and Short-Term Investments
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Cash	26,500	96,900
Cash and Cash Equivalents and Short-Term Investments | Fair Value Measurements on Nonrecurring Basis
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Cash	26,500	96,900
Money market deposit accounts	265,100	217,500
Term deposits	180,000	135,000
Restricted Cash and Cash Equivalents and Restricted Investments
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Restricted cash	89,800	56,400
Restricted Cash and Cash Equivalents and Restricted Investments | Fair Value Measurements on Nonrecurring Basis
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Money market deposit accounts	96,300	7,900
Term deposits	7,800	7,800
Restricted cash	$ 89,800	$ 56,400