Partially-Owned Leasing Subsidiaries (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended					1 Months Ended			1 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Leasing Group Partially-owned subsidiaries subsidiaries	Mar. 31, 2013 Leasing Group Partially-owned subsidiaries	Jun. 30, 2013 Leasing Group TRIP Leasing	Jul. 31, 2013 Leasing Group RIV 2013	May 31, 2013 Leasing Group RIV 2013	Jun. 30, 2013 Leasing Group RIV 2013	May 31, 2013 Leasing Group TRIP Holdings	Mar. 31, 2013 Leasing Group TRIP Holdings	Jun. 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								$ 49.3
Remaining equity commitment outstanding from third parties								107.7
Date through which equity is committed, extended date								May 2019
Trinity guarantees of subsidiary-related activities				0
Purchase price of additional interest in subsidiary									52.3	31.7
Reduction in carrying value of noncontrolling interest from purchase of additional interest in subsidiary										32.3
Proceeds from sale of interests in partially-owned leasing subsidiaries	294.9	0				51.0	94.6		200.3
Carrying value of investment in partially-owned subsidiary								21.8			161.8
Ownership percentage in partially-owned subsidiary								31.00%			45.00%
Equity contribution from TILC to RIV 2013						$ 23.4