Leases - Narrative (Details)	2 Months Ended	3 Months Ended	10 Months Ended	12 Months Ended
	Mar. 12, 2025 USD ($) aircraft_engine	Sep. 30, 2025 aircraftEngine	Dec. 31, 2025 USD ($) a aircraftEngine aircraft_engine aircraft aircraftLeasebackTransaction residential_building_unit	Dec. 31, 2024 USD ($) aircraftLeasebackTransaction	Dec. 31, 2023 USD ($)
Lessee, Lease, Description [Line Items]
Number of aircraft under direct operating leases | aircraft_engine			1
Failed aircraft sale leaseback | aircraftLeasebackTransaction			13	18
Number of spare engines owned | aircraftEngine			18
Total rental expense | $	$ 180,400,000		$ 652,600,000	$ 855,500,000	$ 673,200,000
Aircraft rent | $	120,183,000		428,332,000	541,909,000	381,239,000
Supplemental rent expense | $	$ 7,700,000		$ 17,200,000	$ 36,200,000	$ 14,000,000.0
Area of land | a			8.5
Operating lease not yet commenced, amount, 2026 | $			$ 2,500,000
Operating lease not yet commenced, amount, 2027 and beyond | $			$ 0
Aircraft
Lessee, Lease, Description [Line Items]
Number of aircraft owned | aircraft			48
Number of aircraft unencumbered | aircraft			0
Failed aircraft sale leaseback | aircraft			13
A320 Family | Aircraft
Lessee, Lease, Description [Line Items]
Number of aircraft owned | aircraft			131
Aircraft
Lessee, Lease, Description [Line Items]
Number of aircraft under sale-leaseback transactions | aircraft_engine	2		1
Aircraft | A320 Family
Lessee, Lease, Description [Line Items]
Number of aircraft under operating lease | aircraft			70
Aircraft | Minimum
Lessee, Lease, Description [Line Items]
Operating lease contract term			4 years
Aircraft | Maximum
Lessee, Lease, Description [Line Items]
Operating lease contract term			18 years
Other
Lessee, Lease, Description [Line Items]
Area of land | a			2.6
Number of residential building units | residential_building_unit			200
Other | Maximum
Lessee, Lease, Description [Line Items]
Operating lease contract term			99 years
Spare engines
Lessee, Lease, Description [Line Items]
Number of spare engines | aircraftEngine		14
Number of aircraft under operating lease | aircraft_engine			16
Leased Computer And Office Equipment
Lessee, Lease, Description [Line Items]
Finance lease contract term			5 years