XML 227 R69.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Investments in Affiliated Companies (Investments and Distributions) (Details 3) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 Vessel | Dec. 31, 2012
Schedule of Equity Method Investments [Line Items] |  |  |
Equity Method Investment, Net Sales Proceeds | $ 19.4 us-gaap_EquityMethodInvestmentNetSalesProceeds | $ 55.6 us-gaap_EquityMethodInvestmentNetSalesProceeds | $ 12.5 us-gaap_EquityMethodInvestmentNetSalesProceeds
Number of vessels received |  | 5 gmt_Numberofvesselsreceived |
Payments to Acquire Equity Method Investments | 15.3 us-gaap_PaymentsToAcquireEquityMethodInvestments | 101.3 us-gaap_PaymentsToAcquireEquityMethodInvestments | 29.7 us-gaap_PaymentsToAcquireEquityMethodInvestments
Proceeds from Equity Method Investment, Dividends or Distributions | 54.2 us-gaap_EquityMethodInvestmentDividendsOrDistributions | 47.0 us-gaap_EquityMethodInvestmentDividendsOrDistributions | 53.2 us-gaap_EquityMethodInvestmentDividendsOrDistributions
Rail North America [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Payments to Acquire Equity Method Investments | 0 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_RailNorthAmericaMember | 0 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_RailNorthAmericaMember | 0 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_RailNorthAmericaMember
Proceeds from Equity Method Investment, Dividends or Distributions | 20.0 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_RailNorthAmericaMember | 0 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_RailNorthAmericaMember | 14.9 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_RailNorthAmericaMember
Rail International [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Payments to Acquire Equity Method Investments | 0 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_RailInternationalMember | 0 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_RailInternationalMember | 0 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_RailInternationalMember
Proceeds from Equity Method Investment, Dividends or Distributions | 0 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_RailInternationalMember | 0 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_RailInternationalMember | 0 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_RailInternationalMember
Portfolio Management [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Payments to Acquire Equity Method Investments | 15.3 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_PortfolioManagementMember | 101.3 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_PortfolioManagementMember | 29.7 us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_StatementBusinessSegmentsAxis = gmt_PortfolioManagementMember
Proceeds from Equity Method Investment, Dividends or Distributions | 34.2 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_PortfolioManagementMember | 47.0 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_PortfolioManagementMember | 38.3 us-gaap_EquityMethodInvestmentDividendsOrDistributions / us-gaap_StatementBusinessSegmentsAxis = gmt_PortfolioManagementMember
Enerven Compression Llc [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Reversal of Impairment Loss |  | $ 1.1 gmt_ReversalofImpairmentLoss / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gmt_EnervenCompressionLlcMember |

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

X
- Definition Amount of an impairment reversed related as a result of higher-than-expected proceeds from the sale of an asset. + References No definition available. + Details
Name: | gmt_ReversalofImpairmentLoss
Namespace Prefix: | gmt_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 13 -Article 5 + Details
Name: | us-gaap_EquityMethodInvestmentDividendsOrDistributions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents the amount of net sales proceeds received on disposal of an equity method investment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 35 -Paragraph 35 -URI http://asc.fasb.org/extlink&oid=35687916&loc=d3e32847-111569 + Details
Name: | us-gaap_EquityMethodInvestmentNetSalesProceeds
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=gmt_EnervenCompressionLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=gmt_PortfolioManagementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=gmt_RailInternationalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=gmt_RailNorthAmericaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |