Railcar Leasing and Management Services Group - Future operating lease obligations and future contractual minimum rental revenues (Details) - Railcar Leasing and Management Services Group $ in Millions	Sep. 30, 2018 USD ($)
Railroad transportation equipment leased from independent owner trusts
Future operating lease obligations
Remaining three months of 2018	$ 7.3
2018	28.8
2019	26.1
2020	26.1
2021	24.9
Thereafter	93.1
Total	206.3
Future contractual minimum rental revenues
Remaining three months of 2018	10.7
2018	30.1
2019	20.1
2020	14.7
2021	9.8
Thereafter	8.3
Total	93.7
Operating leases other than leases with the Trusts
Future operating lease obligations
Remaining three months of 2018	3.0
2018	10.5
2019	8.3
2020	7.6
2021	6.8
Thereafter	7.1
Total	43.3
Future contractual minimum rental revenues
Remaining three months of 2018	3.0
2018	9.0
2019	5.8
2020	4.1
2021	3.2
Thereafter	1.3
Total	$ 26.4