Impact of the COVID-19 Pandemic (Details) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended	4 Months Ended	6 Months Ended		12 Months Ended
	Mar. 27, 2020 USD ($)	Jul. 31, 2020 item	Apr. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($)	Jul. 31, 2020 item	Dec. 31, 2020 aircraft	Jun. 30, 2020 USD ($) aircraft	Dec. 31, 2020 aircraft
Unusual Risk or Uncertainty [Line Items]
Liquid Assets				$ 828,300			$ 828,300
Cash and Marketable Securities				762,100			762,100
Line of credit facility, reduction of amount available				66,200			66,200
Grant contra expenses				(151,938)			(151,938)
Maximum borrowing capacity				75,000			75,000
Minimum | COVID-19
Unusual Risk or Uncertainty [Line Items]
Number of daily departures | item		1,200
Maximum
Unusual Risk or Uncertainty [Line Items]
CARES Act, secured loans to airline industry	$ 25,000,000						25,000,000
Maximum | COVID-19
Unusual Risk or Uncertainty [Line Items]
Number of daily departures | item					1,400
PSP agreement
Unusual Risk or Uncertainty [Line Items]
Grants receivable			$ 438,000
Proceeds				306,600
Grant contra expenses				151,900
Deferred grant contra expenses				92,700			92,700
Loan Program
Unusual Risk or Uncertainty [Line Items]
Maximum borrowing capacity				497,000			$ 497,000
CRJ 200 | Sky West Airlines Inc | Delta Connection Agreement
Unusual Risk or Uncertainty [Line Items]
Number of aircraft | aircraft							36
Grant | PSP agreement
Unusual Risk or Uncertainty [Line Items]
Principal amount			336,600
Proceeds				244,600
Forecast | Minimum
Unusual Risk or Uncertainty [Line Items]
Number of daily departures | item		2,500
Forecast | Maximum
Unusual Risk or Uncertainty [Line Items]
Number of daily departures | item		2,600
Forecast | CRJ 200 | Sky West Airlines Inc | Delta Connection Agreement
Unusual Risk or Uncertainty [Line Items]
Number of aircraft removed from service | aircraft						36
Forecast | CRJ 200 | Sky West Airlines Inc | American Prorate Agreement
Unusual Risk or Uncertainty [Line Items]
Number of aircraft removed from service | aircraft								7
Unsecured term loan | PSP agreement
Unusual Risk or Uncertainty [Line Items]
Principal amount			$ 101,400
Debt term			10 years
Proceeds				$ 62,000
Unsecured term loan | First five years | PSP agreement
Unusual Risk or Uncertainty [Line Items]
Interest rate (as a percent)			1.00%
Unsecured term loan | Final five years | PSP agreement
Unusual Risk or Uncertainty [Line Items]
Interest rate (as a percent)			2.00%
Warrant Shares | PSP agreement
Unusual Risk or Uncertainty [Line Items]
Warrants to purchase shares | shares			357,317
Warrants exercise price | $ / shares			$ 28.38
Warrant term			5 years