Flight Equipment held for sale (Details) - Aircraft Held For Sale $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) aircraft	Dec. 31, 2020 aircraft	Dec. 31, 2019 USD ($) aircraft
Flight Equipment Held for Sale
Number of aircraft sold or agreed to be sold	5		8
Flight Equipment, Net | $	$ 175.1		$ 249.6
Forecast
Flight Equipment Held for Sale
Number of aircraft sold or agreed to be sold		5