Partially-Owned Leasing Subsidiaries - Partially-Owned Leasing Subsidiaries (Details)	12 Months Ended
Dec. 31, 2018 USD ($) subsidiary board_member
Noncontrolling Interest [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	5.00%
Partially-owned subsidiaries
Noncontrolling Interest [Line Items]
Trinity guarantees of subsidiary-related activities \| $	$ 0
Partially-owned subsidiaries \| Railcar Leasing and Management Services Group
Noncontrolling Interest [Line Items]
Number of subsidiaries \| subsidiary	2
Number of board members \| board_member	7
Number of TILC designated board members \| board_member	2
Partially-owned subsidiaries \| Railcar Leasing and Management Services Group
Noncontrolling Interest [Line Items]
Carrying value of investment in partially-owned subsidiaries \| $	$ 189,100,000
Weighted average ownership interest	38.00%
Weighted average interest owned by institutional investors	62.00%

Carrying Value of Investment In Partially-Owned Consolidated Subsidiary

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Number of subsidiaries.

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- Definition

Parent Company Guarantees

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=SL6759159-111685

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