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, 2008 $ 25,000 $ 664 $ 1,905,386 $ (386,587) $ 414,900 $ 1,959,363
Balance, shares at Dec. 31, 2008 10 66,419        
Net income       54,568 9,160 63,728
Preferred stock dividends       (2,000)   (2,000)
Common stock dividends       (136,028)   (136,028)
Common unit distributions         (25,100) (25,100)
Common stock offering, value   115 274,711     274,826
Common stock offering, shares   11,500        
Increase (decrease) in noncontrolling interests         3,186 3,186
Redemption of common units for common stock, value   9 24,109   (24,118)  
Redemption of common units for common stock, shares   943        
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value     207     207
Shares issued under Dividend Reinvestment and Stock Purchase Plan, shares   9        
Stock options exercised, value     504     504
Stock options exercised, shares   19        
Stock compensation, value   1 4,503     4,504
Stock compensation, shares   80        
Rebalancing of ownership percent between parent and subsidiaries     66,296   (66,296)  
Balance, value at Dec. 31, 2009 25,000 789 2,275,716 (470,047) 311,732 2,143,190
Balance, shares at Dec. 31, 2009 10 78,970        
Net income       54,900 8,539 63,439
Preferred stock dividends       (2,000)   (2,000)
Common stock dividends       (143,018)   (143,018)
Common unit distributions         (23,543) (23,543)
Increase (decrease) in noncontrolling interests         (321) (321)
Redemption of common units for common stock, value   5 11,047   (11,052)  
Redemption of common units for common stock, shares   487        
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value     158     158
Shares issued under Dividend Reinvestment and Stock Purchase Plan, shares   5        
Stock options exercised, value   1 1,503     1,504
Stock options exercised, shares   55        
Stock compensation, value   1 4,527     4,528
Stock compensation, shares   88        
Rebalancing of ownership percent between parent and subsidiaries     (310)   310  
Balance, value at Dec. 31, 2010 25,000 796 2,292,641 (560,165) 285,665 2,043,937
Balance, shares at Dec. 31, 2010 10 79,605        
Net income       71,420 9,967 81,387
Preferred stock dividends       (1,736)   (1,736)
Common stock dividends       (157,017)   (157,017)
Common unit distributions         (22,794) (22,794)
Common stock offering, value   72 227,302     227,374
Common stock offering, shares   7,188        
Increase (decrease) in noncontrolling interests         (107) (107)
Redemption of common units for common stock, value   8 17,686   (17,694)  
Redemption of common units for common stock, shares   811        
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value     187     187
Shares issued under Dividend Reinvestment and Stock Purchase Plan, shares   6        
Stock options exercised, value   1 3,047     3,048
Stock options exercised, shares   108        
Stock compensation, value   1 4,556     4,557
Stock compensation, shares   82        
Redemption of preferred stock, shares (10)          
Redemption of preferred stock, value (25,000)   164     (24,836)
Rebalancing of ownership percent between parent and subsidiaries     (9,399)   9,399  
Balance, value at Dec. 31, 2011   $ 878 $ 2,536,184 $ (647,498) $ 264,436 $ 2,154,000
Balance, shares at Dec. 31, 2011   87,800