Debt and Other Obligations - Schedule of Interest Expense on Long-term Debt and Capital Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Finance leases	$ 30	$ 57	$ 93
Commitment and other fees	1,655	2,162	2,243
Amortization of deferred financing costs	15,453	14,204	13,282
Total	169,191	139,905	155,611
Accretion of convertible debt and 8.00% senior secured notes	4,210	1,421	1,272
Amortization of debt discount	8,145	13,962	0
Secured Debt
Debt Instrument [Line Items]
Accretion of convertible debt and 8.00% senior secured notes	4,200	1,400	1,300
Interest expense	$ 88,800	46,500	50,600
Secured Debt | 8.00% senior secured notes due in 2025
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%
Interest expense	$ 93,010	47,954	51,897
Fixed-rate term loans
Debt Instrument [Line Items]
Interest expense	37,213	41,446	42,765
Unsecured term loans due through 2031
Debt Instrument [Line Items]
Interest expense	1,363	1,363	1,168
2015-1 EETC Class A
Debt Instrument [Line Items]
Interest expense	10,962	11,874	12,781
2015-1 EETC Class B
Debt Instrument [Line Items]
Interest expense	1,954	2,312	2,669
2015-1 EETC Class C
Debt Instrument [Line Items]
Interest expense	777	3,424	3,988
2017-1 EETC Class AA
Debt Instrument [Line Items]
Interest expense	5,990	6,464	6,938
2017-1 EETC Class A
Debt Instrument [Line Items]
Interest expense	2,159	2,330	2,501
2017-1 EETC Class B
Debt Instrument [Line Items]
Interest expense	1,881	2,016	2,189
2017-1 EETC Class C
Debt Instrument [Line Items]
Interest expense	522	4,367	4,367
Convertible notes
Debt Instrument [Line Items]
Convertible notes	(3,778)	(68)	6,997
Amortization of debt discount and interest expense	14,300	20,300
Convertible notes | Convertible Debt Due in 2026
Debt Instrument [Line Items]
Offset of market-to-market adjustment	(18,100)	(20,300)
Revolving Credit Facility
Debt Instrument [Line Items]
Interest expense	$ 0	$ 0	$ 1,733