XML 108 R67.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Leases Lessee, Schedule of Finance Leases (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($) tankContainer | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) tankContainer
Lessee, Lease, Description [Line Items] |  |  |
Number of railcars received | tankContainer | 728 |  | 21
gatxOperatingLeaseOtherIncome | $ | $ 115.8 | $ 94.6 | $ 81.5

X
- Definition gatxOperatingLeaseOtherIncome + References No definition available. + Details
Name: | gmt_GatxOperatingLeaseOtherIncome
Namespace Prefix: | gmt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of railcars received + References No definition available. + Details
Name: | gmt_Numberofrailcarsreceived
Namespace Prefix: | gmt_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- 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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-3 + Details
Name: | us-gaap_LesseeLeaseDescriptionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration