Summary of Significant Accounting Policies - Summary of Original Cost of Company's Fixed Assets and Accumulated Depreciation or Amortization (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Accumulated Depreciation/ Amortization	$ 200,617	$ 193,457
Property, Plant And Equipment, Excluding Construction In Progress
Property, Plant and Equipment [Line Items]
Original Cost	265,811	265,280
Accumulated Depreciation/ Amortization	200,617	193,457
Aircraft
Property, Plant and Equipment [Line Items]
Original Cost	67,459	67,459
Accumulated Depreciation/ Amortization	50,317	48,011
Spare engines
Property, Plant and Equipment [Line Items]
Original Cost	160,694	160,694
Accumulated Depreciation/ Amortization	124,028	119,575
Rotable parts
Property, Plant and Equipment [Line Items]
Original Cost	28,847	28,335
Accumulated Depreciation/ Amortization	18,664	18,512
Ground equipment
Property, Plant and Equipment [Line Items]
Original Cost	2,912	2,912
Accumulated Depreciation/ Amortization	2,330	2,277
Office equipment
Property, Plant and Equipment [Line Items]
Original Cost	4,776	4,757
Accumulated Depreciation/ Amortization	4,481	4,391
Leasehold improvements
Property, Plant and Equipment [Line Items]
Original Cost	1,123	1,123
Accumulated Depreciation/ Amortization	$ 797	$ 691