Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2020	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	$ 2,500,000		$ 2,900,000
Restricted cash and cash equivalents and restricted short-term investments	1,300,000		1,600,000
Other investments	10,000	$ 10,000	0
Cash and Cash Equivalents and Short-Term Investments
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Cash	219,300		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	219,300		96,900
Money market deposit accounts	203,800		217,500
Term deposits	621,000		135,000
Restricted Cash and Cash Equivalents and Restricted Investments
Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items]
Restricted cash	63,100		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	8,600		7,900
Term deposits	7,800		7,800
Restricted cash	$ 63,100		$ 56,400