Railcar Leasing and Management Services Group - Future operating lease obligations and future contractual minimum rental revenues (Details) $ in Millions	Sep. 30, 2023 USD ($)
Future operating lease obligations
Remaining three months of 2023	$ 5.3
2024	16.9
2025	15.0
2026	13.9
2027	13.4
Thereafter	62.5
Lessee, Operating Lease, Liability, to be Paid, Total	127.0
Railcar Leasing and Management Services Group [Member]
Future operating lease obligations
Remaining three months of 2023	2.7
2024	7.2
2025	6.3
2026	5.9
2027	5.5
Thereafter	3.9
Lessee, Operating Lease, Liability, to be Paid, Total	31.5
Future contractual minimum rental revenues
Remaining three months of 2023	176.3	[1]
2024	622.6	[1]
2025	506.0	[1]
2026	387.4	[1]
2027	282.2	[1]
Thereafter	434.3	[1]
Total	2,408.8	[1]
Railcar Leasing and Management Services Group [Member] | Railroad Transportation Equipment
Future operating lease obligations
Remaining three months of 2023	2.7
2024	7.1
2025	6.3
2026	5.9
2027	5.5
Thereafter	3.9
Lessee, Operating Lease, Liability, to be Paid, Total	31.4
Railcar Leasing and Management Services Group [Member] | Building [Member]
Future operating lease obligations
Lessee, Operating Lease, Liability, to be Paid, Total	0.1
Railcar Leasing and Management Services Group [Member] | Property Lease Guarantee [Member]
Future contractual minimum rental revenues
Guarantor Obligations, Maximum Exposure, Undiscounted	1.0
Railcar Leasing and Management Services Group [Member] | Operating leases
Future contractual minimum rental revenues
Remaining three months of 2023	2.6
2024	6.8
2025	4.6
2026	2.8
2027	0.9
Thereafter	0.3
Total	$ 18.0

[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.