Financial Data of Business Segments (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Profitability
Revenues	$ 337.9	$ 308.7	$ 917.5	$ 860.5
Share of affiliates' earnings	1.8	5.7	33.9	30.6
Total gross income	339.7	314.4	951.4	891.1
Ownership costs	130.3	130.6	393.8	390.6
Other costs and expenses	127.2	124.5	340.1	323.4
Segment profit (loss)	82.2	59.3	217.5	177.1
SG&A	38.5	31.0	112.3	97.3
Income before Income taxes	43.7	28.3	105.2	79.8
Capital Expenditures
Portfolio investments and capital additions	200.0	113.4	460.1	244.5
Investments in Affiliated Companies	547.5		547.5		486.1
Identifiable assets	5,756.5		5,756.5		5,442.4
Rail [Member]
Profitability
Revenues	242.6	221.6	717.1	676.1
Share of affiliates' earnings	(2.0)	(2.1)	13.4	1.8
Total gross income	240.6	219.5	730.5	677.9
Ownership costs	111.8	112.8	341.3	340.3
Other costs and expenses	65.8	74.0	217.9	226.2
Segment profit (loss)	63.0	32.7	171.3	111.4
Capital Expenditures
Portfolio investments and capital additions	133.8	93.0	290.1	181.5
Investments in Affiliated Companies	163.0		163.0		141.0
Identifiable assets	4,448.6		4,448.6		4,292.4
Specialty [Member]
Profitability
Revenues	23.7	21.0	57.2	54.7
Share of affiliates' earnings	3.8	7.8	20.5	28.8
Total gross income	27.5	28.8	77.7	83.5
Ownership costs	12.1	12.2	36.1	35.0
Other costs and expenses	3.9	3.0	10.6	8.3
Segment profit (loss)	11.5	13.6	31.0	40.2
Capital Expenditures
Portfolio investments and capital additions	62.1	19.5	151.4	52.6
Investments in Affiliated Companies	384.5		384.5		345.1
Identifiable assets	862.0		862.0		741.0
ASC [Member]
Profitability
Revenues	71.3	65.9	142.2	128.6
Total gross income	71.3	65.9	142.2	128.6
Ownership costs	5.6	5.6	13.5	13.2
Other costs and expenses	57.2	47.8	110.8	93.4
Segment profit (loss)	8.5	12.5	17.9	22.0
Capital Expenditures
Portfolio investments and capital additions	3.3	0.3	15.9	7.3
Identifiable assets	286.3		286.3		271.3
Other [Member]
Profitability
Revenues	0.3	0.2	1.0	1.1
Total gross income	0.3	0.2	1.0	1.1
Ownership costs	0.8		2.9	2.1
Other costs and expenses	0.3	(0.3)	0.8	(4.5)
Segment profit (loss)	(0.8)	0.5	(2.7)	3.5
Capital Expenditures
Portfolio investments and capital additions	0.8	0.6	2.7	3.1
Identifiable assets	$ 159.6		$ 159.6		$ 137.7