Special Charges (Credits) - Narrative (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($) aircraft	Mar. 31, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($) aircraft employee
Restructuring Cost and Reserve [Line Items]
(Gains) losses on sale of assets and other special charges	$ 112,000	$ 61,000		$ 104,000	$ 77,000
Loss contingency, loss in period	94,000			94,000
Nonoperating unrealized gains (losses)	(40,000)	147,000		(40,000)	125,000
Debt extinguishment costs				7,000
Government assistance received					5,800,000
Government assistance received through unsecured loans					1,700,000
Severance and benefit costs	0	11,000		0	428,000
Impairment of assets	0	$ 59,000		0	$ 59,000
Number of aircraft and related spare engines retired | aircraft		64			64
Nonoperating debt extinguishment and modification fees	0	$ 62,000		7,000	$ 62,000
Nonoperating special termination benefits	0	0		0	(46,000)
Unsecured Debt
Restructuring Cost and Reserve [Line Items]
Long-term debt	$ 400,000			$ 400,000
Payroll Support Program 2 & 3 (PSP 2 & 3) Warrants
Restructuring Cost and Reserve [Line Items]
Issuance of warrants		52,000			99,000
PSP 2 & 3 Note
Restructuring Cost and Reserve [Line Items]
Grant income		$ 1,100,000			$ 2,900,000
Employee Separation | Voluntary Separation Leave Programs
Restructuring Cost and Reserve [Line Items]
Number of employees electing to voluntarily separate from the company | employee					4,500
Nonoperating special termination benefits					$ 46,000
Employee Separation | Voluntary Separation Leave Programs | Full-Time Employees
Restructuring Cost and Reserve [Line Items]
One-time per employee contribution for special termination benefits related to VSL programs			$ 125		125
Employee Separation | Voluntary Separation Leave Programs | Part-Time Employees
Restructuring Cost and Reserve [Line Items]
One-time per employee contribution for special termination benefits related to VSL programs			$ 75		$ 75