Equipment Held for Operating Lease and Notes Receivable - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2021 engine	Mar. 31, 2021 aircraft.	Mar. 31, 2021 marineVessel	Dec. 31, 2020 USD ($)	Dec. 31, 2020 engine	Dec. 31, 2020 aircraft.	Dec. 31, 2020 marineVessel
Lessor, Lease, Description [Line Items]
Equipment held for operating lease, property, equipment, and furnishings, less accumulated depreciation	$ 31,169					$ 31,753
Notes receivable	197,552					158,708
Number of leased assets			295	8	1		291	8	1
Note Receivable
Lessor, Lease, Description [Line Items]
Interest income	$ 2,900	$ 1,000
Minimum | Note Receivable
Lessor, Lease, Description [Line Items]
Note receivable, effective interest rate	6.30%	7.10%
Maximum | Note Receivable
Lessor, Lease, Description [Line Items]
Note receivable, effective interest rate	13.70%	13.70%
Assets Leased to Others
Lessor, Lease, Description [Line Items]
Equipment held for operating lease, property, equipment, and furnishings, less accumulated depreciation	$ 1,887,884					$ 1,886,613