Railcar Leasing and Management Services Group - Future operating lease obligations and future contractual minimum rental revenues (Details) $ in Millions	Sep. 30, 2021 USD ($)
Future operating lease obligations
Remaining three months of 2021	$ 4.0
2022	19.3
2023	17.5
2024	12.9
2025	10.3
Thereafter	72.9
Lessee, Operating Lease, Liability, to be Paid, Total	136.9
Railcar Leasing and Management Services Group [Member]
Future operating lease obligations
Remaining three months of 2021	2.9
2022	11.1
2023	9.3
2024	5.9
2025	4.0
Thereafter	8.1
Lessee, Operating Lease, Liability, to be Paid, Total	41.3
Future contractual minimum rental revenues
Remaining three months of 2021	146.7	[1]
2022	497.6	[1]
2023	374.8	[1]
2024	280.2	[1]
2025	198.0	[1]
Thereafter	344.4	[1]
Total	1,841.7	[1]
Railcar Leasing and Management Services Group [Member] | Building [Member]
Future operating lease obligations
Lessee, Operating Lease, Liability, to be Paid, Total	1.7
Railcar Leasing and Management Services Group [Member] | Railroad Transportation Equipment
Future operating lease obligations
Remaining three months of 2021	2.8
2022	10.8
2023	9.0
2024	5.5
2025	3.7
Thereafter	7.8
Lessee, Operating Lease, Liability, to be Paid, Total	39.6
Railcar Leasing and Management Services Group [Member] | Property Lease Guarantee [Member]
Future contractual minimum rental revenues
Guarantor Obligations, Maximum Exposure, Undiscounted	1.8
Railcar Leasing and Management Services Group [Member] | Operating leases
Future contractual minimum rental revenues
Remaining three months of 2021	1.6
2022	5.0
2023	3.0
2024	2.1
2025	1.2
Thereafter	0.7
Total	$ 13.6

[1] Total contractual minimum rental revenues on operating leases relates to our wholly-owned and partially-owned subsidiaries and sub-lease rental revenues associated with the Leasing Group's operating lease obligations.