Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Impaired Assets to be Disposed of by Method Other than Sale, Fair Value of Asset	$ 191.7		$ 191.7
Impaired Assets to be Disposed of by Method Other than Sale, Carrying Value of Asset	550.0		550.0
Impairment of Long-Lived Assets Held-for-use	358.3
Operating Lease, Impairment Loss	11.1
Restructuring Reserve	0.5		0.5		$ 3.4
Severance Costs	0.0		4.1
Restructuring and Related Cost, Incurred Cost			4.1
Impairment of Long-Lived Assets to be Disposed of	0.0		5.2	$ 0.0
Gain (Loss) on Disposition of Assets	0.3		(3.5)
Tangible Asset Impairment Charges			1.7
Payments for Restructuring			(7.0)
Restructuring Charges	(0.3)	$ 0.0	(5.8)	$ 0.0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.5		0.5
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	0.0		0.0
Impairment of Long-Lived Assets to be Disposed of	0.0		0.0
Gain (Loss) on Disposition of Assets	0.0		0.0
Restructuring Charges	0.0		0.0
Operating Segments [Member] | Rail Products Group [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	0.0		2.6
Impairment of Long-Lived Assets to be Disposed of	0.0		0.0
Gain (Loss) on Disposition of Assets	0.0		0.0
Restructuring Charges	0.0		(2.6)
Operating Segments [Member] | Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	0.0		0.1
Impairment of Long-Lived Assets to be Disposed of	0.0		0.0
Gain (Loss) on Disposition of Assets	0.3		(3.5)
Restructuring Charges	(0.3)		(3.4)
Operating Segments [Member] | Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Severance Costs	0.0		1.4
Impairment of Long-Lived Assets to be Disposed of	0.0		5.2
Gain (Loss) on Disposition of Assets	0.0		0.0
Restructuring Charges	$ 0.0		$ (6.6)