Note 4. Segment Information Segment Information (Details)		3 Months Ended										12 Months Ended
		Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)		Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)		Mar. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) segment		Dec. 31, 2020 USD ($)		Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment												2
External Revenue												$ 1,516,000,000		$ 1,749,700,000		$ 2,752,400,000
Revenues:		$ 472,200,000	$ 419,800,000	$ 293,300,000	$ 330,700,000	$ 359,700,000		$ 396,800,000	$ 439,900,000		$ 553,300,000	1,516,000,000		1,749,700,000		2,752,400,000
Depreciation and amortization												265,700,000		258,500,000		276,500,000
Payments to Acquire Productive Assets												570,800,000		698,100,000		1,210,200,000
Total operating profit (loss)		69,200,000	78,300,000	57,800,000	51,500,000	30,400,000		64,000,000.0	(316,300,000)		67,300,000	256,800,000		(154,600,000)		396,800,000
Asset Impairment Charges						(27,000,000.0)		0	(369,400,000)	[1]	0	0		(396,400,000)		0
Restructuring Charges		2,600,000	100,000	700,000	300,000	(500,000)		(4,700,000)	(300,000)		(5,400,000)	3,700,000		(10,900,000)		(14,600,000)
Nonoperating Income (Expense)		41,100,000	44,500,000	63,500,000	52,500,000	205,900,000	[2]	53,700,000	52,300,000		58,100,000	201,600,000		370,000,000.0		215,600,000
Provision (benefit) for income taxes:		6,500,000	8,300,000	(2,900,000)	4,000,000.0	(42,300,000)		(8,700,000)	(74,000,000.0)		(149,100,000)	15,900,000		(274,100,000)		58,800,000
Gain on sale of discontinued operations, net of provision for income taxes of $51.9, $—, and $—		131,400,000	0	0	0							131,400,000		0		0
Income from discontinued operations, net of provision for income taxes of $3.5, $5.5, and $1.7		(13,200,000)	10,400,000	7,600,000	6,300,000	6,600,000		6,900,000	6,800,000		4,000,000.0	11,100,000		24,300,000		13,700,000
Net income (loss)		139,800,000	$ 35,900,000	$ 4,800,000	$ 1,300,000	(126,600,000)		$ 25,900,000	$ (287,800,000)		$ 162,300,000	181,800,000		(226,200,000)		$ 136,100,000
Total assets		8,235,900,000				8,701,800,000						8,235,900,000		8,701,800,000
Assets of discontinued operations		0				178,500,000						$ 0		$ 178,500,000
Customer Concentration Risk | Revenue Benchmark | Major Customer
Segment Reporting Information [Line Items]
Concentration Risk, Percentage												22.00%		16.00%		11.00%
Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
External Revenue												$ 734,600,000		$ 801,500,000		$ 1,116,300,000
Revenues:												735,300,000		802,300,000		1,117,200,000
Total operating profit (loss)												350,900,000		353,700,000		406,600,000
Restructuring Charges												0		(1,400,000)		(200,000)
Rail Products Group [Member]
Segment Reporting Information [Line Items]
External Revenue												781,400,000		948,200,000		1,635,300,000
Total operating profit (loss)												4,700,000		36,300,000		277,600,000
Restructuring Charges												(300,000)		(1,300,000)		(700,000)
Other Segments [Member]
Segment Reporting Information [Line Items]
External Revenue																800,000
Revenues:																1,200,000
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)												(84,100,000)		(99,700,000)		(107,700,000)
Restructuring Charges												4,000,000.0		(8,200,000)		(13,700,000)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)												355,600,000		390,000,000.0		684,200,000
Total assets		8,649,800,000				8,510,700,000						8,649,800,000		8,510,700,000
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Revenues:												735,300,000		802,300,000		1,117,200,000
Depreciation and amortization												226,000,000.0	[3],[4],[5]	214,700,000	[3],[4]	232,200,000
Payments to Acquire Productive Assets												547,200,000		602,200,000		1,122,200,000
Total operating profit (loss)	[6]											350,900,000		353,700,000		406,600,000
Total assets		7,585,400,000				7,652,100,000						7,585,400,000		7,652,100,000
Operating Segments [Member] | Rail Products Group [Member]
Segment Reporting Information [Line Items]
Revenues:												1,264,800,000		1,609,500,000		2,974,800,000
Depreciation and amortization												33,600,000		35,100,000		34,100,000
Payments to Acquire Productive Assets												21,300,000		78,500,000		85,600,000
Total assets		1,064,400,000				858,600,000						1,064,400,000		858,600,000
Operating Segments [Member] | Corporate Segment [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization												6,100,000		8,700,000		10,200,000
Payments to Acquire Productive Assets												2,300,000		17,400,000		2,400,000
Total assets		365,200,000				832,900,000						365,200,000		832,900,000
Intersegment Eliminations [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues												700,000		800,000		900,000
Intersegment Eliminations [Member] | Rail Products Group [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues												483,400,000		661,300,000		1,339,500,000
Intersegment Eliminations [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues																400,000
MEXICO
Segment Reporting Information [Line Items]
Total assets		414,800,000				267,000,000						414,800,000		267,000,000
Long-Lived Assets		102,000,000				111,900,000						102,000,000		111,900,000
Consolidated Subsidiaries, Leasing [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)												(17,200,000)		(35,200,000)		(164,700,000)
Consolidated Subsidiaries, Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues												(478,500,000)		(652,900,000)		(1,331,100,000)
Revenues:												(478,500,000)		(652,900,000)		(1,331,100,000)
Depreciation and amortization												0		0		0
Payments to Acquire Productive Assets												0		0		0
Total assets	[7]	$ (779,100,000)				$ (820,300,000)						(779,100,000)		(820,300,000)
Consolidated Subsidiaries, Excluding Leasing [Member]
Segment Reporting Information [Line Items]
Total operating profit (loss)												(1,200,000)		(2,400,000)		(400,000)
Consolidated Subsidiaries, Excluding Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment Revenues												(5,600,000)		(9,200,000)		(9,700,000)
Revenues:												(5,600,000)		(9,200,000)		(9,700,000)
Depreciation and amortization												0		0		0
Payments to Acquire Productive Assets												$ 0		$ 0		$ 0

[1] Impairment of long-lived assets during the three months ended June 30, 2020 relates to our small cube covered hopper railcars. See Note 11 for further information.

[2] Other expense during the three months ended December 31, 2020 includes $151.5 million related to the settlement of our Pension Plan. See Note 10 for further information.

[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] Effective January 1, 2020, we revised the estimated useful lives and salvage values of certain railcar types in our lease fleet. This change in estimate resulted in a decrease in depreciation expense of approximately $30.8 million in the years ended December 31, 2021 and 2020. See Note 1 for further information.

[5] In connection with our sustainable railcar conversion program, depreciation expense increased $8.8 million for the year ended December 31, 2021, as a result of the disposal of certain railcar components.

[6] 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.

[7] 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.