Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 1,547.0	$ 1,542.2	$ 1,676.8	$ 1,626.7	$ 1,661.4	$ 1,562.8	$ 1,485.3	$ 1,460.5	$ 6,392.7	$ 6,170.0	$ 4,365.3
Operating Profit (Loss)	358.0	$ 364.9	$ 382.9	$ 333.1	276.5	$ 281.2	$ 302.0	$ 391.3	1,438.9	1,251.0	772.9
Assets	8,885.9				8,695.3				8,885.9	8,695.3	7,274.5
Depreciation & Amortization									266.4	244.6	211.5
Capital Expenditures									1,029.8	464.6	731.0
Intersegment
Segment Reporting Information [Line Items]
Revenues									1,585.4	1,058.0	1,001.3
Total
Segment Reporting Information [Line Items]
Revenues									7,978.1	7,228.0	5,366.6
Operating Profit (Loss)									1,852.0	1,502.7	982.8
Assets	8,388.8				8,114.2				8,388.8	8,114.2	7,098.5
Depreciation & Amortization									258.7	237.3	207.1
Capital Expenditures									1,015.0	455.7	704.9
Corporate
Segment Reporting Information [Line Items]
Operating Profit (Loss)									(152.6)	(119.0)	(73.4)
Assets	1,175.6				1,141.6				1,175.6	1,141.6	728.7
Depreciation & Amortization									7.8	7.4	4.5
Capital Expenditures									14.8	8.9	26.1
Eliminations – Lease subsidiary
Segment Reporting Information [Line Items]
Revenues									(1,164.4)	(710.1)	(756.5)
Operating Profit (Loss)									(259.6)	(133.1)	(135.4)
Assets	(673.0)				(557.2)				(673.0)	(557.2)	(549.7)
Depreciation & Amortization									0.0	0.0	0.0
Capital Expenditures									0.0	0.0	0.0
Eliminations – Other
Segment Reporting Information [Line Items]
Revenues									(421.0)	(347.9)	(244.8)
Operating Profit (Loss)									(0.9)	0.4	(1.1)
Assets	(5.5)				(3.3)				(5.5)	(3.3)	(3.0)
Depreciation & Amortization									(0.1)	(0.1)	(0.1)
Capital Expenditures									0.0	0.0	0.0
Rail Group
Segment Reporting Information [Line Items]
Revenues									3,236.2	3,077.6	2,093.5
Assets	1,245.3				1,322.4				1,245.3	1,322.4	1,063.9
Depreciation & Amortization									38.8	32.7	27.2
Capital Expenditures									84.0	98.3	42.4
Rail Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									1,225.6	739.2	774.0
Rail Group | Total
Segment Reporting Information [Line Items]
Revenues									4,461.8	3,816.8	2,867.5
Operating Profit (Loss)									931.6	724.1	489.7
Construction Products Group
Segment Reporting Information [Line Items]
Revenues									520.6	546.1	508.6
Assets	445.1				459.3				445.1	459.3	464.6
Depreciation & Amortization									24.1	22.7	20.9
Capital Expenditures									28.1	37.1	17.1
Construction Products Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									12.0	5.6	16.4
Construction Products Group | Total
Segment Reporting Information [Line Items]
Revenues									532.6	551.7	525.0
Operating Profit (Loss)									54.5	65.4	52.6
Inland Barge Group
Segment Reporting Information [Line Items]
Revenues									652.9	638.5	576.6
Assets	157.7				177.1				157.7	177.1	170.3
Depreciation & Amortization									10.5	9.3	8.1
Capital Expenditures									5.8	9.7	18.4
Inland Barge Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									0.0	0.0	0.1
Inland Barge Group | Total
Segment Reporting Information [Line Items]
Revenues									652.9	638.5	576.7
Operating Profit (Loss)									117.0	114.4	96.0
Energy Equipment Group
Segment Reporting Information [Line Items]
Revenues									883.6	796.0	536.5
Assets	1,118.3				1,160.0				1,118.3	1,160.0	359.6
Depreciation & Amortization									38.2	33.0	18.2
Capital Expenditures									53.5	56.0	41.5
Energy Equipment Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									230.1	196.3	128.9
Energy Equipment Group | Total
Segment Reporting Information [Line Items]
Revenues									1,113.7	992.3	665.4
Operating Profit (Loss)									150.9	108.1	61.4
Railcar Leasing and Management Services Group
Segment Reporting Information [Line Items]
Revenues									1,091.6	1,106.4	645.4
Assets	5,358.2				4,939.1				5,358.2	4,939.1	4,990.3
Depreciation & Amortization									142.3	130.0	129.0
Capital Expenditures									833.8	245.3	581.1
Railcar Leasing and Management Services Group | Intersegment
Segment Reporting Information [Line Items]
Revenues									13.2	11.9	0.0
Railcar Leasing and Management Services Group | Total
Segment Reporting Information [Line Items]
Revenues									1,104.8	1,118.3	645.4
Operating Profit (Loss)									606.2	516.3	296.8
Depreciation & Amortization									142.3	130.0	129.0
All Other
Segment Reporting Information [Line Items]
Revenues									7.8	5.4	4.7
Assets	$ 64.2				$ 56.3				64.2	56.3	49.8
Depreciation & Amortization									4.8	9.6	3.7
Capital Expenditures									9.8	9.3	4.4
All Other | Intersegment
Segment Reporting Information [Line Items]
Revenues									104.5	105.0	81.9
All Other | Total
Segment Reporting Information [Line Items]
Revenues									112.3	110.4	86.6
Operating Profit (Loss)									$ (8.2)	$ (25.6)	$ (13.7)