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Equipment Held for Operating Lease and Notes Receivable - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 engine	Sep. 30, 2021 aircraft.	Sep. 30, 2021 marineVessel	Dec. 31, 2020 USD ($)	Dec. 31, 2020 engine	Dec. 31, 2020 aircraft.	Dec. 31, 2020 marineVessel
Lessor, Lease, Description [Line Items]
Notes receivable	$ 196,146		$ 196,146					$ 158,708
Number of leased assets					313	8	1		291	8	1
Note Receivable
Lessor, Lease, Description [Line Items]
Interest income	3,600	$ 3,100	$ 10,100	$ 6,700
Minimum \| Note Receivable
Lessor, Lease, Description [Line Items]
Note receivable, effective interest rate			6.30%	6.30%
Maximum \| Note Receivable
Lessor, Lease, Description [Line Items]
Note receivable, effective interest rate			12.20%	16.60%
Equipment Held For Operating Lease
Lessor, Lease, Description [Line Items]
Equipment held for operating lease, property, equipment, and furnishings, less accumulated depreciation	$ 1,971,252		$ 1,971,252					$ 1,886,613