Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 905.5	$ 1,184.9	$ 1,782.8	$ 2,372.8
Operating Profit (Loss)	135.2	191.6	251.8	395.0
Intersegment
Segment Reporting Information [Line Items]
Total revenues	178.5	329.3	422.4	697.8
Intersegment | Eliminations – Lease subsidiary
Segment Reporting Information [Line Items]
Total revenues	(115.9)	(252.1)	(296.9)	(535.4)
Operating Profit (Loss)	(13.6)	(45.9)	(42.5)	(111.4)
Intersegment | Eliminations – Other
Segment Reporting Information [Line Items]
Total revenues	(62.6)	(77.2)	(125.5)	(162.4)
Operating Profit (Loss)	(2.1)	0.2	(4.5)	1.6
Total
Segment Reporting Information [Line Items]
Total revenues	1,084.0	1,514.2	2,205.2	3,070.6
Operating Profit (Loss)	189.2	272.0	372.1	564.2
Corporate
Segment Reporting Information [Line Items]
Operating Profit (Loss)	(38.3)	(34.7)	(73.3)	(59.4)
Rail Group
Segment Reporting Information [Line Items]
Total revenues	335.4	427.7	621.4	970.9
Rail Group | Intersegment
Segment Reporting Information [Line Items]
Total revenues	130.5	265.5	322.8	569.2
Rail Group | Total
Segment Reporting Information [Line Items]
Total revenues	465.9	693.2	944.2	1,540.1
Operating Profit (Loss)	37.0	88.8	87.7	246.0
Construction Products Group
Segment Reporting Information [Line Items]
Total revenues	130.7	141.7	251.6	263.3
Construction Products Group | Intersegment
Segment Reporting Information [Line Items]
Total revenues	0.6	4.1	2.8	7.4
Construction Products Group | Total
Segment Reporting Information [Line Items]
Total revenues	131.3	145.8	254.4	270.7
Operating Profit (Loss)	22.3	21.5	37.9	37.4
Inland Barge Group
Segment Reporting Information [Line Items]
Total revenues	33.5	118.3	96.2	229.1
Inland Barge Group | Intersegment
Segment Reporting Information [Line Items]
Total revenues	0.0	0.0	0.0	0.0
Inland Barge Group | Total
Segment Reporting Information [Line Items]
Total revenues	33.5	118.3	96.2	229.1
Operating Profit (Loss)	0.5	14.3	6.9	26.9
Energy Equipment Group
Segment Reporting Information [Line Items]
Total revenues	212.2	199.1	440.0	431.6
Energy Equipment Group | Intersegment
Segment Reporting Information [Line Items]
Total revenues	26.3	41.5	53.9	82.4
Energy Equipment Group | Total
Segment Reporting Information [Line Items]
Total revenues	238.5	240.6	493.9	514.0
Operating Profit (Loss)	24.3	34.9	54.1	72.3
Railcar Leasing and Management Services Group
Segment Reporting Information [Line Items]
Total revenues	191.9	296.1	370.5	473.9
Railcar Leasing and Management Services Group | Intersegment
Segment Reporting Information [Line Items]
Total revenues	0.2	0.5	0.5	1.2
Railcar Leasing and Management Services Group | Total
Segment Reporting Information [Line Items]
Total revenues	192.1	296.6	371.0	475.1
Operating Profit (Loss)	110.8	117.7	195.8	191.9
All Other
Segment Reporting Information [Line Items]
Total revenues	1.8	2.0	3.1	4.0
All Other | Intersegment
Segment Reporting Information [Line Items]
Total revenues	20.9	17.7	42.4	37.6
All Other | Total
Segment Reporting Information [Line Items]
Total revenues	22.7	19.7	45.5	41.6
Operating Profit (Loss)	$ (5.7)	$ (5.2)	$ (10.3)	$ (10.3)