Consolidated Statements of Cash Flows Parenthetical - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Payments to Acquire Leasing Assets Net of Sold Railcars Owned One Year or Less Net Cost	$ 54.0	$ 319.3

Payments to Acquire Leasing Assets Net of Sold Railcars Owned One Year or Less Net Cost

No definition available.

Name:	trn_PaymentstoAcquireLeasingAssetsNetofSoldRailcarsOwnedOneYearorLessNetCost
Namespace Prefix:	trn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration