Impact of COVID-19 - COVID-19 Legislation Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended	8 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Unusual or Infrequent Item, or Both [Line Items]
Issuance of warrants		$ 2,146,000
Payroll Support Program, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Proceeds received from Payroll Support Program				$ 344,400,000
Shares of common stock subject to warrants issued to the United States Treasury (in shares)				520,797
Strike price (USD per share)				$ 14.08
Issuance of warrants				$ 3,900,000
Payroll Support Program, Grant
Unusual or Infrequent Item, or Both [Line Items]
Amount recorded as special credits for unused PSP proceeds due to COVID-19				$ 267,200,000
Payroll Support Program 2
Unusual or Infrequent Item, or Both [Line Items]
Proceeds received from Payroll Support Program			$ 212,100,000
Shares of common stock subject to warrants issued to the United States Treasury (in shares)	137,753		137,753
Strike price (USD per share)	$ 24.42		$ 24.42
Issuance of warrants			$ 2,800,000
Payroll Support Program 2, Grant
Unusual or Infrequent Item, or Both [Line Items]
Amount recorded as special credits for unused PSP proceeds due to COVID-19	$ 175,600,000
CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Number of warrants issued as a percent of outstanding common stock	100.00%		100.00%
Social security tax, employer, deferral, CARES Act	$ 23,200,000		$ 23,200,000
Payroll Support Program 3
Unusual or Infrequent Item, or Both [Line Items]
Proceeds received from Payroll Support Program	$ 197,900,000
Shares of common stock subject to warrants issued to the United States Treasury (in shares)	80,539		80,539	80,539
Strike price (USD per share)	$ 36.45		$ 36.45
Issuance of warrants			$ 1,500,000
Amount recorded as deferred salaries, wages and benefits for unused PSP proceeds due to COVID-19	$ 86,400,000		$ 86,400,000
Payroll Support Program 3, grant, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Proceeds received from Payroll Support Program	167,000,000.0
Amount recorded as special credits for unused PSP proceeds due to COVID-19	$ 80,600,000
CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Number of warrants issued as a percent of outstanding common stock	1.00%		1.00%
Notes payable To United States Treasury | Payroll Support Program, Low-Interest Loan, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Principal amount				$ 73,300,000
Term				10 years
Notes payable To United States Treasury | Payroll Support Program, Low-Interest Loan, CARES Act | Payroll Support Program 3
Unusual or Infrequent Item, or Both [Line Items]
Term			10 years
Notes payable To United States Treasury | Payroll Support Program 2, Low-Interest Loan, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Term			10 years
Notes payable To United States Treasury | Payroll Support Program 2, Low-Interest Loan, CARES Act | Payroll Support Program 2
Unusual or Infrequent Item, or Both [Line Items]
Principal amount	$ 33,600,000		$ 33,600,000
Term	10 years
Notes payable To United States Treasury | Payroll Support Program 3, Low-Interest Loan, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Term		10 years
Notes payable To United States Treasury | Payroll Support Program 3, Low-Interest Loan, CARES Act | Payroll Support Program 3
Unusual or Infrequent Item, or Both [Line Items]
Principal amount	$ 29,400,000		$ 29,400,000