Note 4. Segment Information Segment Information (Details) $ in Millions		3 Months Ended									12 Months Ended
		Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2022 USD ($) segment		Dec. 31, 2021 USD ($)		Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment											2
External Revenue											$ 1,977.3		$ 1,516.0		$ 1,749.7
Revenues:		$ 591.2	$ 496.6	$ 416.8	$ 472.7	$ 472.2	$ 419.8	$ 293.3	$ 330.7		1,977.3		1,516.0		1,749.7
Depreciation and amortization											276.4		265.7		258.5
Capital expenditures											966.8		570.8		698.1
Total operating profit (loss)		113.5	92.7	73.0	54.8	69.2	78.3	57.8	51.5		334.0		256.8		(154.6)
Impairment of long-lived assets										$ (369.4)	0.0		0.0		(396.4)
Restructuring activities, net		0.0	0.0	(1.0)	0.0	2.6	0.1	0.7	0.3		(1.0)		3.7		(10.9)
Other (income) expense		60.5	54.4	50.7	41.9	41.1	44.5	63.5	52.5		207.5		201.6		370.0
Provision (benefit) for income taxes:		10.2	8.6	5.8	3.0	6.5	8.3	(2.9)	4.0		27.6		15.9		(274.1)
Income (loss) from discontinued operations, net of provision (benefit) for income taxes of $(1.1), $3.5, and $5.5		(6.6)	(3.4)	(3.4)	(6.9)	(13.2)	10.4	7.6	6.3		(20.3)		11.1		24.3
Gain (loss) on sale of discontinued operations, net of provision (benefit) for income taxes of $(1.4), $51.9, and $—		0.0	0.0	(4.6)	(1.1)	131.4	0.0	0.0	0.0		(5.7)		131.4		0.0
Net income (loss)		36.2	$ 26.3	$ 8.5	$ 1.9	139.8	$ 35.9	$ 4.8	$ 1.3		72.9		181.8		$ (226.2)
Total assets		8,724.3				8,235.9					$ 8,724.3		$ 8,235.9
Customer Concentration Risk | Revenue Benchmark | Major Customer
Segment Reporting Information [Line Items]
Concentration Risk, Percentage											17.00%		22.00%		16.00%
Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
External Revenue											$ 769.8		$ 734.6		$ 801.5
Total operating profit (loss)											423.3		350.9		353.7
Restructuring activities, net													0.0		(1.4)
Rail Products Group [Member]
Segment Reporting Information [Line Items]
External Revenue											1,207.5		781.4		948.2
Total operating profit (loss)											59.1		4.7		36.3
Restructuring activities, net													(0.3)		(1.3)
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)											(80.8)		(84.1)		(99.7)
Restructuring activities, net													4.0		(8.2)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)											482.4		355.6		390.0
Total assets		9,220.4				8,649.8					9,220.4		8,649.8
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Revenues:											770.6		735.3		802.3
Depreciation and amortization	[2]										236.4	[1]	226.0	[1],[3]	214.7	[3]
Capital expenditures											928.8		547.2		602.2
Total operating profit (loss)	[2]										423.3		350.9		353.7
Total assets		7,779.9				7,585.4					7,779.9		7,585.4
Operating Segments [Member] | Rail Products Group [Member]
Segment Reporting Information [Line Items]
Revenues:											2,074.7		1,264.8		1,609.5
Depreciation and amortization											34.8		33.6		35.1
Capital expenditures											35.7		21.3		78.5
Total assets		1,440.5				1,064.4					1,440.5		1,064.4
Operating Segments [Member] | Corporate Segment [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization											5.2		6.1		8.7
Capital expenditures											2.3		2.3		17.4
Total assets		267.2				365.2					267.2		365.2
Intersegment Eliminations [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues											0.8		0.7		0.8
Intersegment Eliminations [Member] | Rail Products Group [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues											867.2		483.4		661.3
MEXICO
Segment Reporting Information [Line Items]
Total assets		571.7				414.8					571.7		414.8
Long-Lived Assets		96.3				102.0					96.3		102.0
Consolidated Subsidiaries, Leasing [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)											(65.2)		(17.2)		(35.2)
Consolidated Subsidiaries, Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues											(867.2)		(478.5)		(652.9)
Revenues:											(867.2)		(478.5)		(652.9)
Depreciation and amortization											0.0		0.0		0.0
Capital expenditures											0.0		0.0		0.0
Total assets	[4]	$ (763.3)				$ (779.1)					(763.3)		(779.1)
Consolidated Subsidiaries, Excluding Leasing [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)											(1.4)		(1.2)		(2.4)
Consolidated Subsidiaries, Excluding Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues											(0.8)		(5.6)		(9.2)
Revenues:											(0.8)		(5.6)		(9.2)
Depreciation and amortization											0.0		0.0		0.0
Capital expenditures											$ 0.0		$ 0.0		$ 0.0

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

[2] Operating profit includes: depreciation; 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] Additionally, depreciation expense related to our small cube covered hopper railcars decreased by approximately $7.0 million for the years ended December 31, 2021 and 2020 as a result of the impairment charge recorded in the second quarter of 2020 related to these railcars.

[4] 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 8 for a further discussion regarding our investment in our partially-owned leasing subsidiaries and the related indebtedness.