Consolidated Statement of Stockholders' Equity (Unaudited) (USD $) In Millions	Total		Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Trinity Stockholders' Equity	Noncontrolling Interest
Beginning Balance at Dec. 31, 2010	$ 1,845.7		$ 81.7	$ 606.1	$ 1,200.5	$ (95.5)	$ (28.0)	$ 1,764.8	$ 80.9
Beginning Balance, Shares at Dec. 31, 2010			81.7				(1.9)
Net income	88.8				86.1			86.1	2.7
Other comprehensive income, net of tax:
Currency translation adjustments	(0.1)					(0.1)		(0.1)
Change in unrealized loss on derivative financial instruments	(3.5)					(3.2)		(3.2)	(0.3)
Comprehensive net income	85.2							82.8	2.4
Cash dividends on common stock	(20.8)				(20.8)			(20.8)
Restricted shares issued, net	6.0			5.1			0.9	6.0
Restricted shares issued, net, Shares							0.2
Stock options exercised	1.8			(0.6)			2.4	1.8
Stock options exercised, Shares							0.2
Reclassification of purchase of additional interest in TRIP Holdings				15.5		(15.5)
Ending Balance at Sep. 30, 2011	1,917.9	[1]	81.7	626.1	1,265.8	(114.3)	(24.7)	1,834.6	83.3
Ending Balance, Shares at Sep. 30, 2011			81.7				(1.5)
Beginning Balance at Jun. 30, 2011
Net income	31.6
Other comprehensive income, net of tax:
Change in unrealized loss on derivative financial instruments								(5.2)
Comprehensive net income								26.7
Ending Balance at Sep. 30, 2011	$ 1,917.9	[1]	$ 81.7					$ 1,834.6
Ending Balance, Shares at Sep. 30, 2011			81.7

[1] Unaudited