Contingencies (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014 Railcar
Contingencies (Textual) [Abstract]
Total accruals	$ 18.1
Number of tank cars to be voluntarily recertified by the Company	948
Minimum possible loss	8.2
Maximum possible loss	28.4
Highway Products Litigation
Contingencies (Textual) [Abstract]
Alleged damages, exclusive of attorney's fees, costs, and interest	775.7
Total accruals	0
Train Derailment
Contingencies (Textual) [Abstract]
Total accruals	0
Number of tank cars owned by the Company and leased to third party	13
Number of tank cars manufactured by the Company	35
Number of tank cars involved in derailment	72
Environmental and workplace matters
Contingencies (Textual) [Abstract]
Total accruals	$ 10.1