Property and Equipment - Additional Information (Detail) $ in Thousands		12 Months Ended
	Jul. 01, 2019 USD ($) Aircraft	Dec. 31, 2019 USD ($) Aircraft	Dec. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)	Sep. 30, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Other income		$ 2,505	$ 14,396
Right-of-use assets		24,026		$ 70,892
Flight Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Fair market value		15,832
Aircraft lease termination costs		$ 19,353
Descrtption of aircraft engine cycle		On one hundred and forty dollars per remaining engine cycle with a minimum value of $50 per engine, and each of the aircraft airframes was assigned a fair market value of $100.
Right-of-use assets		$ 26,275
Offset by lease liabilities		1,182
Unamortized engine overhauls		$ 9,535
Number of engine acquired | Aircraft		28
Leasehold improvements book value		$ 738
Number of aircraft acquired | Aircraft		14
CRJ-200 [Member] | Bombardier Inc [Member]
Property, Plant and Equipment [Line Items]
Amount paid in installment					$ 25,192
Number of aircraft delivered | Aircraft	14
Remaining installment amount	$ 8,212
Other income		$ 2,537	$ 14,443