Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net	$ 0.7	$ (0.3)	$ 1.0	$ (5.8)
Gain (Loss) on Disposition of Assets	0.7	0.3	1.4	3.5
Employee severance costs			0.4	4.1
Non-cash impact of restructuring activities				5.2
Restructuring Reserve	0.4		0.4		$ 1.4
Charges and adjustments			0.4
Payments			(1.4)
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	0.4		0.4
Railcar Leasing and Management Services Group [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net			0.0	0.0
Gain (Loss) on Disposition of Assets	0.0	0.0	0.0	0.0
Employee severance costs			0.0	0.0
Non-cash impact of restructuring activities				0.0
Rail Products Group [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net			(0.3)	(2.6)
Gain (Loss) on Disposition of Assets	0.0	0.0	0.0	0.0
Employee severance costs			0.3	2.6
Non-cash impact of restructuring activities				0.0
Other Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net			1.4	3.4
Gain (Loss) on Disposition of Assets	0.7	0.3	1.4	3.5
Employee severance costs			0.0	0.1
Non-cash impact of restructuring activities				0.0
Corporate Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring activities, net			(0.1)	(6.6)
Gain (Loss) on Disposition of Assets	$ 0.0	$ 0.0	0.0	0.0
Employee severance costs			$ 0.1	1.4
Non-cash impact of restructuring activities				$ 5.2