Debt and Other Obligations - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Debt Instrument [Line Items]
Commitment and other fees	$ 415	$ 830	$ 1,243	$ 1,785
Amortization of deferred financing costs	3,845	3,202	11,674	10,634
Total	41,260	23,708	121,933	91,712
Accretion expense			3,157	782
8.00% senior secured notes
Debt Instrument [Line Items]
Accretion expense	1,100	300	3,200	800
Interest expense	$ 22,200	$ 10,200	$ 66,600	$ 30,600
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	$ 10,461	$ 69,757	$ 31,382
Fixed-rate term loans
Debt Instrument [Line Items]
Interest expense	9,111	10,273	28,012	31,442
Unsecured term loans | Unsecured term loans
Debt Instrument [Line Items]
Interest expense	344	344	1,020	1,020
Class A 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	2,758	2,985	8,312	8,986
Class B 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	492	581	1,506	1,772
Class C 2015-1 EETC
Debt Instrument [Line Items]
Interest expense	0	856	777	2,629
Class AA 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	1,495	1,615	4,537	4,893
Class A 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	539	582	1,636	1,764
Class B 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	470	503	1,423	1,525
Class C 2017-1 EETC
Debt Instrument [Line Items]
Interest expense	0	1,104	522	3,275
Convertible notes
Debt Instrument [Line Items]
Convertible notes	(1,468)	(9,641)	(8,510)	(9,442)
Convertible notes | Convertible notes due 2026
Debt Instrument [Line Items]
Total	4,400	5,400	9,900	14,900
Offset of market-to-market adjustment	5,900	15,000	18,400	24,300
Finance leases
Debt Instrument [Line Items]
Interest expense	$ 7	$ 13	$ 24	$ 47