Derivative Financial Instruments Contingent Forward Sale Contract (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2012 Contingent forward sale contract [Member]	Sep. 30, 2012 Contingent forward sale contract [Member]	Oct. 02, 2012 Series A-1 Preferred Stock [Member] RailAmerica [Member] The Carlyle Group [Member]	Sep. 28, 2012 Class A common shares [Member]
Proceeds from issuance of stock							$ 350,000,000
Contingent forward sale contract mark-to-market expense	$ 0	$ 50,106,000	$ 0	$ 50,106,000	$ 50,100,000	$ 50,106,000
Share Price								$ 66.86