Debt (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended			12 Months Ended		1 Months Ended												12 Months Ended				12 Months Ended		12 Months Ended		1 Months Ended
	Dec. 31, 2011	Dec. 31, 2009	Jul. 31, 2011	Dec. 31, 2011 Convertible subordinated notes [Member]	Dec. 31, 2010 Convertible subordinated notes [Member]	Feb. 28, 2011 TILC Warehouse Facility Non Recourse Leasing [Member] Installment	Dec. 31, 2011 TILC Warehouse Facility Non Recourse Leasing [Member]	Dec. 31, 2011 TRIP Holdings Senior Secured Notes [Member]	Dec. 31, 2011 TRIP Master Funding Secured Railcar Equipment Notes [Member]	Jul. 31, 2011 TRIP Master Funding Secured Railcar Equipment Notes [Member]	Dec. 31, 2011 TRIP Master Funding Secured Railcar Equipment Class A-1a Notes [Member]	Dec. 31, 2011 TRIP Master Funding Secured Railcar Equipment Class A-1b Notes [Member]	Dec. 31, 2011 TRIP Master Funding Secured Railcar Equipment Class A-2 Notes [Member]	Dec. 31, 2011 Corporate Revolving Credit Facility [Member]	Oct. 20, 2011 Corporate Revolving Credit Facility [Member]	Jul. 31, 2011 TRIP Holdings Warehouse Loan Non Recourse Leasing [Member]	Jun. 30, 2007 TRIP Holdings Warehouse Loan Non Recourse Leasing [Member]	Dec. 31, 2011 2006 Secured Railcar Equipment Notes Non Recourse [Member] Trinity Rail Leasing V [Member]	May 31, 2006 2006 Secured Railcar Equipment Notes Non Recourse [Member] Trinity Rail Leasing V [Member]	Dec. 31, 2011 Promissory notes [Member] Trinity Rail Leasing VI [Member]	May 31, 2008 Promissory notes [Member] Trinity Rail Leasing VI [Member]	Dec. 31, 2011 2009 Secured Railcar Equipment Notes Non Recourse [Member] Trinity Rail Leasing VII [Member]	Nov. 30, 2009 2009 Secured Railcar Equipment Notes Non Recourse [Member] Trinity Rail Leasing VII [Member]	Dec. 31, 2011 2010 Secured Railcar Equipment Notes Non Recourse [Member] Trinity Rail Leasing [Member]	Oct. 31, 2010 2010 Secured Railcar Equipment Notes Non Recourse [Member] Trinity Rail Leasing [Member]	Nov. 30, 2010 6.5% Senior Notes [Member]	Dec. 31, 2011 6.5% Senior Notes [Member]	Dec. 31, 2011 Unsecured Debt [Member]
Debt (Textual) [Abstract]
Revolving credit facility							$ 475.0								$ 425.0
Revolving credit facility expiration date before extended	Oct. 20, 2016
Used revolving credit facility for letter of credit														74.1
Availability of the revolving credit facility							166.5							350.9
Borrowing under revolving credit facility exclusive of letters of credit	0
Letter of credit maturing current year	69.2
Amended credit facility, description of variable rate reference rate basis														LIBOR
Percentage points added to LIBOR to compute Interest rates on the amended credit facility														1.50%
Amended credit facility, description of variable rate reference rate basis, alternative computation														prime
Percentage points added to prime to compute Interest rates on the amended credit facility, alternative computation														0.50%
Subordinated Long-term Debt, Noncurrent				450.0
Interest rate on notes				3.875%				8.00%			4.37%		6.02%					5.90%				6.66%		5.19%				6.50%
Maturity date				Jun. 01, 2036														May 14, 2036				Nov. 16, 2039		Oct. 16, 2040
Date before which notes can't be redeemed				Jun. 01, 2018
Rate at which LIBOR portion of debt is fixed due to issuance of Interest rate swap																				4.13%
Value at which notes can be redeemed for cash				at 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest (including any contingent interest) up to, but excluding, the redemption date
Percentage of principal amount used in cash redemption value computation	100.00%
Capital in excess of par value related to the convertible subordinated notes' conversion options				92.8	92.8
Effective annual interest rate based upon the estimated market interest rate				8.42%
Conversion price of convertible subordinated notes				$ 51.41
Number of shares issuable in exchange of Convertible Subordinated Notes				8,753,161
TILC warehouse facility							308.5
Interest at a defined index rate plus a margin for advances under the facility							2.30%
Period for which interest rate swap issued																				7 years
Rate increase on each of seventh and eighth anniversary dates of issuance																				0.50%
Rate increase on each of tenth anniversary dates of issuance																				2.00%
Additional period for warehouse loan facility						2 years
Maturity date of warehouse loan facility						February, 2013
Number of installments payable for amounts outstanding at maturity, absent renewal						3
Installment payable date, installment one						August 2013
Installment payable date, installment two						February 2014
Debt instrument maturity period																				30 years
Installment payable date, installment three						August 2014
Debt Instrument, Face Amount										857.0						175.0	1,190.0		355.0		572.2		238.3		369.2
Debt instrument final maturity date								Jul. 06, 2014
Debt instrument, Yield to call percentage for redemptions or other prepayments on or prior to January 15, 2013								12.00%
Debt instrument, Yield to call percentage for redemptions or other prepayments after January 15, 2013								15.00%
Trinity portion of the TRIP Holdings Senior Secured Notes			112.0
Percentage points added to LIBOR												2.50%								1.50%
Total Outstanding											211.1	119.3	509.6											354.3
Amount Outstanding																		269.3		465.5		218.4
Term loan agreement, total		61.0
Capital lease obligation, total		56.6
Unsecured senior Notes redeemed																										201.5
Maturity year of unsecured senior notes																											2014
Redemption price as percentage of principal amount																										102.167%
Expenses related to redemption																										$ 5.9
Extended period for credit facility															4 years
Debt Instrument, final maturity date description									in July 2041
Debt instrument interest rate features											payable monthly	payable monthly	payable monthly