Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 1,103.8	$ 1,111.7	$ 1,184.9	$ 1,187.9	$ 1,547.0	$ 1,542.2	$ 1,676.8	$ 1,626.7	$ 4,588.3	$ 6,392.7	$ 6,170.0
Operating Profit (Loss)	163.6	$ 183.6	$ 191.6	$ 203.4	358.0	$ 364.9	$ 382.9	$ 333.1	742.2	1,438.9	1,251.0
Assets	9,125.3				8,885.9				9,125.3	8,885.9	8,695.3
Depreciation & Amortization									283.0	266.4	244.6
Capital Expenditures									933.4	1,029.8	464.6
Intersegment
Segment Reporting Information [Line Items]
Revenues									1,347.2	1,585.4	1,058.0
Total
Segment Reporting Information [Line Items]
Revenues									5,935.5	7,978.1	7,228.0
Operating Profit (Loss)									1,052.1	1,852.0	1,502.7
Assets	8,850.9				8,388.8				8,850.9	8,388.8	8,114.2
Depreciation & Amortization									274.4	258.7	237.3
Capital Expenditures									915.4	1,015.0	455.7
Corporate
Segment Reporting Information [Line Items]
Operating Profit (Loss)									(131.0)	(152.6)	(119.0)
Assets	1,079.3				1,175.6				1,079.3	1,175.6	1,141.6
Depreciation & Amortization									8.7	7.8	7.4
Capital Expenditures									18.0	14.8	8.9
Rail Group
Segment Reporting Information [Line Items]
Revenues									2,006.9	3,236.2	3,077.6
Assets	1,014.1				1,245.3				1,014.1	1,245.3	1,322.4
Depreciation & Amortization									41.7	38.8	32.7
Capital Expenditures									29.2	84.0	98.3
Rail Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									1,070.4	1,225.6	739.2
Rail Group | Total
Segment Reporting Information [Line Items]
Revenues									3,077.3	4,461.8	3,816.8
Operating Profit (Loss)									459.9	931.6	724.1
Construction Products Group
Segment Reporting Information [Line Items]
Revenues									510.6	520.6	546.1
Assets	470.3				445.1				470.3	445.1	459.3
Depreciation & Amortization									23.8	24.1	22.7
Capital Expenditures									49.9	28.1	37.1
Construction Products Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									12.6	12.0	5.6
Construction Products Group | Total
Segment Reporting Information [Line Items]
Revenues									523.2	532.6	551.7
Operating Profit (Loss)									72.6	54.5	65.4
Inland Barge Group
Segment Reporting Information [Line Items]
Revenues									403.0	652.9	638.5
Assets	120.8				157.7				120.8	157.7	177.1
Depreciation & Amortization									8.4	10.5	9.3
Capital Expenditures									3.2	5.8	9.7
Inland Barge Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									0.1	0.0	0.0
Inland Barge Group | Total
Segment Reporting Information [Line Items]
Revenues									403.1	652.9	638.5
Operating Profit (Loss)									45.3	117.0	114.4
Energy Equipment Group
Segment Reporting Information [Line Items]
Revenues									834.7	883.6	796.0
Assets	1,035.7				1,118.3				1,035.7	1,118.3	1,160.0
Depreciation & Amortization									36.6	38.2	33.0
Capital Expenditures									25.0	53.5	56.0
Energy Equipment Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									178.0	230.1	196.3
Energy Equipment Group | Total
Segment Reporting Information [Line Items]
Revenues									1,012.7	1,113.7	992.3
Operating Profit (Loss)									133.1	150.9	108.1
Railcar Leasing and Management Services Group
Segment Reporting Information [Line Items]
Revenues									824.9	1,091.6	1,106.4
Assets	6,095.7				5,358.2				6,095.7	5,358.2	4,939.1
Depreciation & Amortization									156.2	142.3	130.0
Capital Expenditures									799.1	833.8	245.3
Railcar Leasing and Management Services Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									2.1	13.2	11.9
Railcar Leasing and Management Services Group | Total
Segment Reporting Information [Line Items]
Revenues									827.0	1,104.8	1,118.3
Operating Profit (Loss)									360.1	606.2	516.3
Depreciation & Amortization									156.2	142.3	130.0
All Other
Segment Reporting Information [Line Items]
Revenues									8.2	7.8	5.4
Assets	114.3				64.2				114.3	64.2	56.3
Depreciation & Amortization									7.7	4.8	9.6
Capital Expenditures									9.0	9.8	9.3
All Other | Intersegment
Segment Reporting Information [Line Items]
Revenues									84.0	104.5	105.0
All Other | Total
Segment Reporting Information [Line Items]
Revenues									92.2	112.3	110.4
Operating Profit (Loss)									(18.9)	(8.2)	(25.6)
Consolidated Subsidiaries, Leasing [Member]
Segment Reporting Information [Line Items]
Assets	(798.1)				(673.0)				(798.1)	(673.0)	(557.2)
Depreciation & Amortization									0.0	0.0	0.0
Capital Expenditures									0.0	0.0	0.0
Consolidated Subsidiaries, Leasing [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues									(1,021.9)	(1,164.4)	(710.1)
Operating Profit (Loss)									(178.2)	(259.6)	(133.1)
Consolidated Subsidiaries, Excluding Leasing [Member]
Segment Reporting Information [Line Items]
Assets	$ (6.8)				$ (5.5)				(6.8)	(5.5)	(3.3)
Depreciation & Amortization									(0.1)	(0.1)	(0.1)
Capital Expenditures									0.0	0.0	0.0
Consolidated Subsidiaries, Excluding Leasing [Member] | Intersegment
Segment Reporting Information [Line Items]
Revenues									(325.3)	(421.0)	(347.9)
Operating Profit (Loss)									$ (0.7)	$ (0.9)	$ 0.4