Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net	$ 0.1	$ (4.7)	$ 1.1	$ (10.5)
Gain (Loss) on Disposition of Assets	0.2		1.6	3.5
Employee severance costs	0.1	3.4	0.5	7.5
Non-cash impact of restructuring activities		0.7		5.9
Restructuring Reserve	0.3		0.3		$ 1.4
Charges and adjustments			0.5
Payments			(1.6)
Loss on Contract Termination		0.6		0.6
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.3		0.3
Railcar Leasing and Management Services Group [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net	0.0	(1.4)	0.0	(1.4)
Gain (Loss) on Disposition of Assets	0.0		0.0	0.0
Employee severance costs	0.0	1.4	0.0	1.4
Non-cash impact of restructuring activities		0.0		0.0
Loss on Contract Termination		0.0		0.0
Rail Products Group [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net	(0.1)	(2.2)	(0.4)	(4.8)
Gain (Loss) on Disposition of Assets	0.0		0.0	0.0
Employee severance costs	0.1	1.3	0.4	3.9
Non-cash impact of restructuring activities		0.7		0.7
Loss on Contract Termination		0.2		0.2
Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net	0.2	(0.1)	1.6	3.3
Gain (Loss) on Disposition of Assets	0.2		1.6	3.5
Employee severance costs	0.0	0.1	0.0	0.2
Non-cash impact of restructuring activities		0.0		0.0
Loss on Contract Termination		0.0		0.0
Corporate Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net	0.0	(1.0)	(0.1)	(7.6)
Gain (Loss) on Disposition of Assets	0.0		0.0	0.0
Employee severance costs	$ 0.0	0.6	$ 0.1	2.0
Non-cash impact of restructuring activities		0.0		5.2
Loss on Contract Termination		$ 0.4		$ 0.4