Goodwill (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Goodwill by Segment
Goodwill	$ 773.2us-gaap_Goodwill	$ 278.2us-gaap_Goodwill
Goodwill impairment charges	0us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss
Rail Group
Goodwill by Segment
Goodwill	134.6	134.6
Accumulated goodwill impairment losses	325.0	325.0
Construction Products Group
Goodwill by Segment
Goodwill	128.3	126.9
Energy Equipment Group
Goodwill by Segment
Goodwill	508.5	14.9
Railcar Leasing and Management Services Group
Goodwill by Segment
Goodwill	$ 1.8	$ 1.8

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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