Summary of Significant Accounting Policies - Airframe and Engine Maintenance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Deferred costs for heavy maintenance	$ 74,100	$ 75,200	$ 176,000
Deferred heavy maintenance, gross	633,900	570,600
Accumulated heavy maintenance amortization	884,858	680,230
Airframe and Engine Maintenance Costs [Abstract]
Total maintenance, materials and repairs	159,502	111,227	143,575
Flight hour-based maintenance expense
Airframe and Engine Maintenance Costs [Abstract]
Total maintenance, materials and repairs	81,591	52,092	78,253
Non-flight hour-based maintenance expense
Airframe and Engine Maintenance Costs [Abstract]
Total maintenance, materials and repairs	77,911	59,135	65,322
Heavy maintenance and major overhaul
Property, Plant and Equipment [Line Items]
Amortization of heavy maintenance	91,929	88,927	$ 63,364
Heavy Maintenance
Property, Plant and Equipment [Line Items]
Accumulated heavy maintenance amortization	$ 303,900	$ 222,700