Partially-Owned Leasing Subsidiaries (Details Textual) (USD $) In Millions, unless otherwise specified	9 Months Ended				1 Months Ended				1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Leasing Group Partially-owned subsidiaries subsidiaries	Sep. 30, 2013 Leasing Group TRIP Leasing	Aug. 31, 2013 Leasing Group RIV 2013	Jul. 31, 2013 Leasing Group RIV 2013	May 31, 2013 Leasing Group RIV 2013	Sep. 30, 2013 Leasing Group RIV 2013	May 31, 2013 Leasing Group TRIP Holdings	Mar. 31, 2013 Leasing Group TRIP Holdings	Sep. 30, 2013 Leasing Group TRIP Holdings
Schedule of Investments [Line Items]
Number of subsidiaries			2
Number of board members			7
Number of TILC designated board members			2
Number of railcars owned				0
Date through which equity funding is committed								May 2016
Remaining equity commitment outstanding								$ 27.9
Remaining equity commitment outstanding from third parties								63.4
Date through which equity is committed, extended date								May 2019
Trinity guarantees of subsidiary-related activities			0
Purchase price of additional interest in TRIP Holdings	84.0	0							52.3	31.7
Reduction in carrying amount of noncontrolling interest from purchase of additional interest in TRIP Holdings	(84.2)									32.3
Proceeds from sale of interests in partially-owned leasing subsidiaries	296.7	0					94.6		200.3
Carrying value of investment in partially-owned subsidiary								44.2			163.2
Ownership percentage in partially-owned subsidiary								31.00%			45.00%
Contribution from TILC to RIV 2013						23.4
Contribution from third-party investors to RIV 2013	50.0	0				50.0
Purchase of equity interests by one investor from other investors					$ 2.5