Railcar Leasing and Management Services Group - Selected consolidating financial information for the Leasing Group (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Consolidating Financial Information
Cash and cash equivalents	$ 73.9	$ 179.2
Property, plant, and equipment, net	6,746.8	6,334.4
Restricted cash	114.2	171.6
Debt:
Recourse	650.0	400.0
Less: unamortized discount	(0.3)	(0.3)
Less: unamortized debt issuance costs	(2.2)	(2.3)
Debt and Capital Lease Obligations	647.5	397.4
Non-recourse debt	3,852.0	3,666.9
Non-recourse, Unamortized Discount	2.3	2.7
Less: unamortized debt issuance costs	(30.8)	(32.4)
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	3,818.9	3,631.8
Total debt	4,466.4	4,029.2
Net deferred tax liabilities	743.9	731.6
Railcar Leasing and Management Services Group [Member]
Debt:
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	3,818.9	3,631.8
Operating Segments
Consolidating Financial Information
Property, plant, and equipment, net	7,586.3	7,162.1
Net deferred profit on railcars sold to the Leasing Group
Consolidating Financial Information
Property, plant, and equipment, net	(839.5)	(827.7)
Wholly-owned subsidiaries
Debt:
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	2,513.7	2,316.6
Wholly-owned subsidiaries | Railcar Leasing and Management Services Group [Member]
Debt:
Less: unamortized debt issuance costs	(18.6)	(19.7)
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	2,513.7	2,316.6
Wholly-owned subsidiaries | Operating Segments | Railcar Leasing and Management Services Group [Member]
Consolidating Financial Information
Cash and cash equivalents	4.5	6.0
Property, plant, and equipment, net	5,406.2	4,976.5
Restricted cash	85.1	134.9
Debt:
Recourse	0.0	0.0
Less: unamortized discount	0.0	0.0
Less: unamortized debt issuance costs	0.0	0.0
Debt and Capital Lease Obligations	0.0	0.0
Non-recourse debt	2,534.6	2,339.0
Non-recourse, Unamortized Discount	2.3	2.7
Less: unamortized debt issuance costs	(18.6)	(19.7)
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	2,513.7	2,316.6
Total debt	2,513.7	2,316.6
Net deferred tax liabilities	806.2	797.6
Partially-owned subsidiaries
Consolidating Financial Information
Restricted cash	29.0	36.6
Debt:
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	1,305.2	1,315.2
Partially-owned subsidiaries | Railcar Leasing and Management Services Group [Member]
Debt:
Non-recourse debt	1,317.4	1,327.9
Less: unamortized debt issuance costs	(12.2)	(12.7)
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	1,305.2	1,315.2
Partially-owned subsidiaries | Operating Segments | Railcar Leasing and Management Services Group [Member]
Consolidating Financial Information
Cash and cash equivalents	0.0	0.0
Property, plant, and equipment, net	1,810.3	1,814.7
Restricted cash	29.0	36.6
Debt:
Recourse	0.0	0.0
Less: unamortized discount	0.0	0.0
Less: unamortized debt issuance costs	0.0	0.0
Debt and Capital Lease Obligations	0.0	0.0
Non-recourse debt	1,317.4	1,327.9
Non-recourse, Unamortized Discount	0.0	0.0
Less: unamortized debt issuance costs	(12.2)	(12.7)
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	1,305.2	1,315.2
Total debt	1,305.2	1,315.2
Net deferred tax liabilities	1.0	1.0
Manufacturing/ Corporate
Consolidating Financial Information
Property, plant, and equipment, net	369.8	370.9
Manufacturing/ Corporate | Operating Segments | Manufacturing/ Corporate
Consolidating Financial Information
Cash and cash equivalents	69.4	173.2
Property, plant, and equipment, net	369.8	370.9
Restricted cash	0.1	0.1
Debt:
Recourse	650.0	400.0
Less: unamortized discount	(0.3)	(0.3)
Less: unamortized debt issuance costs	(2.2)	(2.3)
Debt and Capital Lease Obligations	647.5	397.4
Non-recourse debt	0.0	0.0
Non-recourse, Unamortized Discount	0.0	0.0
Less: unamortized debt issuance costs	0.0	0.0
Non-recourse debt, net of unamortized discount and unamortized debt issuance costs	0.0	0.0
Total debt	647.5	397.4
Net deferred tax liabilities	(63.3)	(67.0)
2018 secured railcar equipment notes | Wholly-owned subsidiaries | Railcar Leasing and Management Services Group [Member]
Debt:
Less: unamortized discount	$ (0.2)	$ (0.2)