Shareholders' Equity Preferred Stock (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Class of Stock [Line Items]
Payments for Repurchase of Redeemable Preferred Stock			$ 113,797,000	$ 177,955,000
Other Preferred Stock Dividends and Adjustments	(3,196,000)	0	(2,713,000)	(5,932,000)
Cumulative Preferred Stock [Member]
Class of Stock [Line Items]
Stock Repurchased During Period, Shares			750,243
Stock Repurchased During Period, Value			18,800,000
Payments for Repurchase of Redeemable Preferred Stock			17,700,000
Issuance Costs [Member] | Cumulative Preferred Stock [Member]
Class of Stock [Line Items]
Other Preferred Stock Dividends and Adjustments			(618,000)
Gain (Loss) Repurchase of Redeemable Preferred Shares (Member) | Cumulative Preferred Stock [Member]
Class of Stock [Line Items]
Other Preferred Stock Dividends and Adjustments			483,000
Series J Preferred Stock [Member] | Cumulative Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage			6.625%
Preferred Stock, Redemption Price Per Share	$ 250.00		$ 250.00
Stock Redeemed or Called During Period, Shares			384,530
Payments for Repurchase of Redeemable Preferred Stock			96,100,000
Other Preferred Stock Dividends and Adjustments			$ (3,200,000)