Net Investment in Finance Leases Net Investment in Finance Leases (Details) $ in Thousands	Jun. 30, 2020 USD ($) Aircraft	Dec. 31, 2019 USD ($) Aircraft
Receivables [Abstract]
Capital Leased Assets, Number of Units | Aircraft	24	29
Capital Leases, Net Investment in Direct Financing Leases [Abstract]
Lease receivable	$ 122,460	$ 164,816
Unguaranteed residual value of flight equipment	200,043	254,580
Capital Leases Investment In Direct Financing And Sales Type Leases before Allowance	322,503	419,396
Financing Receivable, Allowance for Credit Loss, Current	(2,972)	0
Net investment in leases, net of allowance for credit losses of $2,972 and $0, respectively	319,531	$ 419,396
Receivable in Remainder of Fiscal Year	20,936
Receivable in Year Two	34,793
Receivable in Year Three	23,960
Receivable in Year Four	23,234
Receivable in Year Five	8,950
Thereafter	32,406
Total	144,279
Sales-type and Direct Financing Leases, Lease Receivable, Undiscounted Excess Amount	(122,460)
Difference between the Present Value and Undiscounted Sales Type and Direct Financing Lease Receivable	$ 21,819