Note 4. Segment Information Segment Information (Details) $ in Millions		12 Months Ended
		Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment		2
External Revenue		$ 2,983.3	$ 1,977.3	$ 1,516.0
Revenues:		2,983.3	1,977.3	1,516.0
Depreciation and amortization		293.2	276.4	265.7
Capital expenditures		710.1	966.8	570.8
Total operating profit		417.0	334.0	256.8
Restructuring activities, net		2.2	(1.0)	3.7
Other (income) expense		268.0	207.5	201.6
Provision (benefit) for income taxes:		9.0	27.6	15.9
Income (loss) from discontinued operations, net of provision (benefit) for income taxes of $(3.6), $(1.1), and $3.5		(13.4)	(20.3)	11.1
Gain (loss) on sale of discontinued operations, net of provision (benefit) for income taxes of $—, $(1.4), and $51.9		0.0	(5.7)	131.4
Net income		126.6	72.9	181.8
Total assets		8,906.5	8,724.3
Operating Segment Assets		9,370.4	9,220.4
MEXICO
Segment Reporting Information [Line Items]
Total assets		590.0	571.7
Long-Lived Assets		96.1	96.3
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets		96.1	96.3
Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
External Revenue		870.0	769.8	734.6
Total operating profit		428.5	423.3	350.9
Rail Products Group [Member]
Segment Reporting Information [Line Items]
External Revenue		2,113.3	1,207.5	781.4
Total operating profit		129.4	59.1	4.7
Corporate and Other
Segment Reporting Information [Line Items]
Total operating profit		$ (108.3)	$ (80.8)	$ (84.1)
Major Customer | Revenue Benchmark | Customer Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration Risk, Percentage		13.00%	17.00%	22.00%
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating profit		$ 557.9	$ 482.4	$ 355.6
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Revenues:		870.9	770.6	735.3
Depreciation and amortization	[1]	244.6	236.4	226.0
Capital expenditures		671.5	928.8	547.2
Total operating profit	[2]	428.5	423.3	350.9
Total assets		7,895.7	7,779.9
Operating Segments [Member] | Rail Products Group [Member]
Segment Reporting Information [Line Items]
Revenues:		2,703.0	2,074.7	1,264.8
Depreciation and amortization		43.7	34.8	33.6
Capital expenditures		37.1	35.7	21.3
Total assets		1,474.7	1,440.5
Operating Segments [Member] | Corporate and Other
Segment Reporting Information [Line Items]
Depreciation and amortization		4.9	5.2	6.1
Capital expenditures		1.5	2.3	2.3
Total assets		286.3	267.2
Intersegment Eliminations [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues		0.9	0.8	0.7
Intersegment Eliminations [Member] | Rail Products Group [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues		589.7	867.2	483.4
Consolidated Subsidiaries, Leasing [Member]
Segment Reporting Information [Line Items]
Total operating profit		(36.1)	(65.2)	(17.2)
Consolidated Subsidiaries, Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues		(589.7)	(867.2)	(478.5)
Revenues:		(589.7)	(867.2)	(478.5)
Depreciation and amortization		0.0	0.0	0.0
Capital expenditures		0.0	0.0	0.0
Total assets	[3]	(750.2)	(763.3)
Consolidated Subsidiaries, Excluding Leasing [Member]
Segment Reporting Information [Line Items]
Total operating profit		1.3	(1.4)	(1.2)
Consolidated Subsidiaries, Excluding Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues		(0.9)	(0.8)	(5.6)
Revenues:		(0.9)	(0.8)	(5.6)
Depreciation and amortization		0.0	0.0	0.0
Capital expenditures		$ 0.0	$ 0.0	$ 0.0

[1] Depreciation and amortization expense includes $5.6 million, $12.1 million, and $8.8 million for the years ended December 31, 2023, 2022, and 2021, respectively, related to the disposal of certain railcar components associated with our sustainable railcar conversion program.

[2] Operating profit includes: depreciation and amortization; fleet operating costs, which include maintenance, compliance, freight, and storage; rent and ad valorem taxes; and selling, engineering, and administrative expenses. Amortization of deferred profit on railcars sold from the Rail Products Group to the Leasing Group is included in the operating profits of the Leasing Group, resulting in the recognition of depreciation expense based on our original manufacturing cost of the railcars. Interest expense is not a component of operating profit and includes the effect of hedges.

[3] Net deferred profit on railcars sold to the Leasing Group consists of intersegment profit that is eliminated in consolidation. Net deferred profit and the related deferred tax impact are included as adjustments to the property, plant, and equipment, net and deferred income taxes line items, respectively, in the Eliminations – Lease Subsidiary column above to reflect the net book value of the railcars purchased by the Leasing Group from the Rail Products Group based on manufacturing cost. See Note 5 and Note 9 for a further discussion regarding our investment in our partially-owned leasing subsidiaries and the related indebtedness.