Debt and Other Obligations - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Commitment and other fees	$ 412	$ 415	$ 1,247	$ 1,243
Amortization of deferred financing costs	3,556	3,845	10,625	11,674
Total	54,135	41,260	163,251	121,933
Accretion expense			3,157	3,157
8.00% senior secured notes
Debt Instrument [Line Items]
Accretion expense	1,100	1,100	3,200	3,200
Interest expense	$ 22,200	$ 22,200	$ 66,600	$ 66,600
8.00% senior secured notes | 8.00% Senior Secured Notes Due 2025
Debt Instrument [Line Items]
Stated interest rate percentage	8.00%	8.00%	8.00%	8.00%	8.00%
Interest expense	$ 23,252	$ 23,252	$ 69,757	$ 69,757
Fixed-rate term loans
Debt Instrument [Line Items]
Interest expense	17,275	9,111	52,630	28,012
Unsecured term loans | Unsecured term loans
Debt Instrument [Line Items]
Interest expense	343	344	1,028	1,020
Class A 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	2,531	2,758	7,649	8,312
Class B 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	0	492	446	1,506
Class C 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	0	0	0	777
Class AA 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	1,385	1,495	4,208	4,537
Class A 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	503	539	1,517	1,636
Class B 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	438	470	1,324	1,423
Class C 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	0	0	0	522
Convertible notes
Debt Instrument [Line Items]
Convertible notes	4,432	(1,468)	12,795	(8,510)
Convertible notes | Convertible notes due 2026
Debt Instrument [Line Items]
Total	4,400	4,400	13,300	9,900
Offset of market-to-market adjustment		(5,900)	(500)	(18,400)
Finance leases
Debt Instrument [Line Items]
Interest expense	$ 8	$ 7	$ 25	$ 24