Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity (Preferred Stock) (Narrative) (Details)

v3.20.4
Shareholders' Equity (Preferred Stock) (Narrative) (Details)
12 Months Ended
Dec. 30, 2019
USD ($)
Nov. 04, 2019
USD ($)
$ / shares
shares
Jan. 03, 2018
USD ($)
Dec. 31, 2020
USD ($)
item
$ / shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Class of Stock [Line Items]              
Shares Amount       $ 944,750,000 $ 944,750,000    
Redeemable preferred stock, redemption price per share | $ / shares       $ 25.00      
Proceeds from Issuance of Redeemable Preferred Stock         316,038,000    
Preferred Redemption allocation         11,007,000    
Distributions to preferred shareholders       $ 48,186,000 $ 54,346,000 $ 52,573,000  
Number of quarterly dividends in arrearage before preferred shareholders can elect additional board members | item       6      
Number of additional board members the preferred shareholders can elect in the case of an excess arrearage of quarterly dividends | item       2      
Dividends in arrears       $ 0      
Series U Preferred Stock [Member]              
Class of Stock [Line Items]              
Cumulative preferred stock, dividend rate 5.75%            
Shares Amount $ 230,000,000.0            
Series V Preferred Stock [Member]              
Class of Stock [Line Items]              
Cumulative preferred stock, dividend rate 5.70%            
Shares Amount $ 110,000,000.0            
Series Z Preferred Stock [Member]              
Class of Stock [Line Items]              
Cumulative preferred stock, dividend rate   4.875%   4.875%      
Shares Amount   $ 325,000,000.0   $ 325,000,000      
Number of stock issued in sale | shares   13,000,000          
Redeemable preferred stock, redemption price per share | $ / shares   $ 25.00          
Non-callable period for Preferred Units   5 years          
Mandatory redemption | shares   0          
Proceeds from Issuance of Redeemable Preferred Stock   $ 316,000,000.0          
Series T Preferred Stock [Member]              
Class of Stock [Line Items]              
Cumulative preferred stock, dividend rate     6.00%        
Shares Amount     $ 130,000,000.0        
Series T Preferred Stock [Member] | Redemption, Period Two [Member]              
Class of Stock [Line Items]              
Preferred Redemption allocation             $ 4,100,000