Related Party Transactions (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 engine	Jun. 30, 2020 aircraft.	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($) engine aircraft.
Related Party Transaction [Line Items]
Maintenance reserve revenue	$ 29,986	$ 26,475			$ 50,514	$ 51,825
Number of engines sold | engine			0			0
WMES
Related Party Transaction [Line Items]
Number of aircrafts sold | aircraft.				0		5
Proceeds from sale of aircraft						$ 75,500
Number of engines sold			0	0
WMES | Other Income | Asset Management
Related Party Transaction [Line Items]
Maintenance reserve revenue	$ 300	$ 600			$ 800	$ 1,100
CASC Willis
Related Party Transaction [Line Items]
Number of aircrafts sold | aircraft.				0		0
Number of engines sold | engine			0			0