Summary of Significant Accounting Policies Lessee Accounting (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term		5 years		5 years
Lessee, Operating Lease, Option to Terminate				one year
Finance Lease, Principal Payments				$ 0.0
Operating lease expense		$ 5.3	$ 4.4	10.6	$ 8.7
Cash flows from operating activities				10.6	8.7
Right-of-use assets recognized in exchange for new lease liabilities				2.6	$ 6.4
Right-of-use assets (1)	[1]	98.7		98.7		$ 100.6
Lease liabilities (2)	[2]	$ 115.0		$ 115.0		$ 118.2
Weighted average remaining lease term		8 years 10 months 24 days		8 years 10 months 24 days		9 years 3 months 18 days
Weighted average discount rate (3)	[3]	3.70%		3.70%		3.60%
Remaining six months of 2024		$ 10.5		$ 10.5
2025		19.3		19.3
2026		17.6		17.6
2027		16.3		16.3
2028		12.8		12.8
Thereafter		58.2		58.2
Lessee, Operating Lease, Liability, to be Paid, Total		134.7		134.7
Less: Present value adjustment		(19.7)		(19.7)
Railcars on Lease [Member]
Lessee, Lease, Description [Line Items]
Remaining six months of 2024		4.4		4.4
2025		8.3		8.3
2026		7.7		7.7
2027		7.2		7.2
2028		5.1		5.1
Thereafter		6.8		6.8
Lessee, Operating Lease, Liability, to be Paid, Total		39.5		39.5
Operating & Administrative Assets [Member]
Lessee, Lease, Description [Line Items]
Remaining six months of 2024		6.1		6.1
2025		11.0		11.0
2026		9.9		9.9
2027		9.1		9.1
2028		7.7		7.7
Thereafter		51.4		51.4
Lessee, Operating Lease, Liability, to be Paid, Total		$ 95.2		$ 95.2
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year		1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		13 years		13 years

[1] Included in other assets in our Consolidated Balance Sheets.

[2] Included in other liabilities in our Consolidated Balance Sheets.

[3] As the rate implicit in our leases is not readily determinable, we use the incremental borrowing rate of our Trinity Industries Leasing Company ("TILC") warehouse loan facility for railcar leases or our revolving credit facility for operating and administrative leases at lease commencement to determine the present value of lease payments.