Other Assets (Details) - USD ($) $ in Thousands	Feb. 29, 2020	Dec. 31, 2019
Principal components of other assets
Deferred income tax asset	$ 636	$ 1,007
Lease incentives and lease premiums, net of amortization of $63,010 and $71,851, respectively	103,161	112,923
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	13,083	333
Deposit Assets	39,038	33,754
Operating Lease, Right-of-Use Asset	9,148	9,329
Other assets	41,551	43,863
Total other assets	206,617	201,209
Amortization of lease incentives and lease premiums	$ 63,010	$ 71,851