Impact of the COVID-19 Pandemic (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 23, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Unusual or Infrequent Item, or Both [Line Items]
Liquid assets		$ 1,542,400
Cash and marketable securities		836,400
Line of credit facility, reduction of amount available		41,000
Borrowed amount		3,140,774		$ 3,236,002
Maximum borrowing capacity		75,000
PSP Extension Agreement
Unusual or Infrequent Item, or Both [Line Items]
Principal amount		233,100
PSP 3 Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Proceeds received	$ 125,000
Grant | PSP Extension Agreement
Unusual or Infrequent Item, or Both [Line Items]
Principal amount		193,200
Grant | PSP Extension Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Principal amount	35,000
Forecast | PSP 3 Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Principal amount			$ 250,000
Unsecured term loan | PSP Extension Agreement
Unusual or Infrequent Item, or Both [Line Items]
Principal amount		$ 39,900
Debt term		10 years
Unsecured term loan | First five years | PSP Extension Agreement
Unusual or Infrequent Item, or Both [Line Items]
Interest rate (as a percent)		1.00%
Unsecured term loan | Final five years | PSP Extension Agreement
Unusual or Infrequent Item, or Both [Line Items]
Interest rate (as a percent)		2.00%
Secured loan
Unusual or Infrequent Item, or Both [Line Items]
Borrowed amount		$ 60,000
Secured loan | COVID-19
Unusual or Infrequent Item, or Both [Line Items]
Liquid assets		$ 665,000
Promissory Note | PSP Extension Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Increase in debt instrument principal amount	10,500
Promissory Note | PSP 3 Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Principal amount	$ 7,500
Percentage of increase in principal amount	30.00%
Promissory Note | PSP 3 Agreement | Minimum
Unusual or Infrequent Item, or Both [Line Items]
Interest rate (as a percent)		0.00%
Promissory Note | PSP 3 Agreement | Maximum
Unusual or Infrequent Item, or Both [Line Items]
Principal amount		$ 45,000
Promissory Note | Until the fifth anniversary of the Closing Date | PSP 3 Agreement
Unusual or Infrequent Item, or Both [Line Items]
Interest rate (as a percent)		1.00%
Promissory Note | Thereafter until the tenth anniversary of the Closing Date | PSP 3 Agreement
Unusual or Infrequent Item, or Both [Line Items]
Interest rate (as a percent)		2.00%
Warrant Shares | PSP Extension Agreement
Unusual or Infrequent Item, or Both [Line Items]
Warrants to purchase shares		98,815
Warrants exercise price		$ 40.41
Warrant term		5 years
Warrant Shares | PSP Extension Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Warrants to purchase shares	25,958
Warrants exercise price	$ 40.41
Warrant Shares | PSP 3 Agreement
Unusual or Infrequent Item, or Both [Line Items]
Warrants exercise price		$ 57.47
Warrant Shares | PSP 3 Agreement | Subsequent event
Unusual or Infrequent Item, or Both [Line Items]
Warrants to purchase shares	13,058
Warrant Shares | PSP 3 Agreement | Maximum
Unusual or Infrequent Item, or Both [Line Items]
Warrants to purchase shares		78,317