Consolidated Statement Of Changes In Equity (USD $)
In Thousands
Preferred Stock [Member]
Common Stock [Member]
Additional Paid-In Capital [Member]
Dividends In Excess Of Net Earnings [Member]
Noncontrolling Interests In Subsidiaries [Member]
Total
Balance, value at Dec. 31, 2010$ 25,000$ 796$ 2,292,641$ (560,165)$ 285,665$ 2,043,937
Balance, shares at Dec. 31, 20101079,605    
Net income   55,2267,72362,949
Preferred stock dividends   (1,664) (1,664)
Common stock dividends   (117,507) (117,507)
Common unit distributions    (17,305)(17,305)
Common stock offering, value 72227,302  227,374
Common stock offering, shares 7,188    
Decrease in noncontrolling interest    (107)(107)
Redemption of common units for common stock, value 25,189 (5,191) 
Redemption of common units for common stock, shares 237    
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value  139  139
Shares issued under Dividend Reinvestment and Stock Purchase Plan, shares 4    
Stock options exercised, value 13,047  3,048
Stock options exercised, shares 108    
Stock compensation  2,393  2,393
Accrued redemption of preferred stock(25,000) 164  (24,836)
Rebalancing of ownership percent between parent and subsidiaries  (9,438) 9,438 
Balance, value at Sep. 30, 2011 $ 871$ 2,521,437$ (624,110)$ 280,223$ 2,178,421
Balance, shares at Sep. 30, 20111087,142