The net gain (loss) arising from the lessor's sale of assets held- or available-for-lease under contractual arrangements classified as operating leases.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 40
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=77911379&loc=d3e44908-112734

Name:	us-gaap_GainLossOnSaleOfLeasedAssetsNetOperatingLeases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Summary of Significant Accounting Policies - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net gain (loss) on sale of leasing equipment	$ 4,857	$ 6,196	$ 7,519	$ 8,469	$ 7,999	$ 7,055	$ 11,105	$ 9,218	$ 27,041	$ 35,377	$ 35,812
Long Lived Assets Held-for-sale, Name [Domain]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net gain (loss) on sale of leasing equipment									$ (5,299)	$ (3,933)	$ 3