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	Jun. 30, 2019 USD ($)
Future operating lease obligations
Minimum Lease Payments, Sale Leaseback Transactions, Remainder of Fiscal Year	$ 5.2
Minimum Lease Payments, Sale Leaseback Transactions, within Two Years	9.1
Minimum Lease Payments, Sale Leaseback Transactions, within Three Years	8.2
Minimum Lease Payments, Sale Leaseback Transactions, within Four Years	7.5
Minimum Lease Payments, Sale Leaseback Transactions, within Five Years	5.5
Thereafter	3.3
Total	38.8
Operating leases
Future contractual minimum rental revenues
Future Minimum Sublease Rentals, Sale Leaseback Transactions, Remainder of Fiscal Year	5.1
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Two Years	7.4
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Three Years	5.5
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Four Years	3.8
Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Five Years	1.5
Thereafter	0.5
Total	$ 23.8