Debt - Components of debt (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	$ 5,707.6	$ 5,607.6
Recourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	704.3	624.1
Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	5,003.3	4,983.5
Level 1
Debt Instrument [Line Items]
Long-term Debt, Fair Value	1,806.6	1,662.8
Level 2
Debt Instrument [Line Items]
Long-term Debt, Fair Value	389.8	387.5
Level 3
Debt Instrument [Line Items]
Long-term Debt, Fair Value	3,217.8	3,194.0
Fair Value, Inputs, Level 1, 2 and 3
Debt Instrument [Line Items]
Long-term Debt, Fair Value	5,414.2	5,244.3
Corporate Segment [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	704.9	624.9
Less: unamortized debt issuance costs	0.6	0.8
Senior Notes [Member] \| Corporate Segment [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	399.9	399.9
Debt Instrument, Unamortized Discount	0.1	0.1
Wholly Owned Subsidiaries [Member] \| Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	3,826.9	3,800.7
Wholly Owned Subsidiaries [Member] \| Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	3,846.5	3,821.8
Less: unamortized debt issuance costs	19.6	21.1
Wholly Owned Subsidiaries [Member] \| Railcar Leasing and Management Services Group [Member] \| Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	3,826.9	3,800.7
Wholly Owned Subsidiaries [Member] \| Secured Debt [Member] \| Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	2,344.9	2,384.0
Debt Instrument, Unamortized Discount	0.4	0.3
Wholly Owned Subsidiaries [Member] \| 2017 Secured Railcar Equipment Notes [Member] [Domain] \| Promissory Notes [Member] \| Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	705.4	716.0
Debt Instrument, Unamortized Discount	5.1	5.6
Partially-Owned Subsidiaries [Member] \| Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	1,176.4	1,182.8
Partially-Owned Subsidiaries [Member] \| Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Less: unamortized debt issuance costs	9.2	9.8
Partially-Owned Subsidiaries [Member] \| Railcar Leasing and Management Services Group [Member] \| Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	1,176.4	1,182.8
Partially-Owned Subsidiaries [Member] \| Secured Debt [Member] \| Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	1,185.6	1,192.6
Debt Instrument, Unamortized Discount	0.3	0.3
Revolving Credit Facility [Member] \| Line of Credit [Member] \| Corporate Segment [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	305.0	225.0
Revolving Credit Facility [Member] \| TILC [Member] \| TILC Warehouse Facility [Member] \| Line of Credit [Member] \| Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	$ 796.2	$ 721.8

Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs

No definition available.

Name:	trn_DebtNetOfUnamortizedDiscountGrossOfUnamortizedDebtIssuanceCosts
Namespace Prefix:	trn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28541-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the aggregate of total long-term debt, including current maturities and short-term debt.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant