Net Investment in Finance Leases Narrative (Details) - Aircraft	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Capital Leased Assets, Number of Units	24	29

The number of units (items of property) under capital lease arrangements.

No definition available.

Name:	us-gaap_CapitalLeasedAssetsNumberOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant