Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.3
Shareholders' Equity (Preferred Stock) (Narrative) (Details)
3 Months Ended 9 Months Ended
Jan. 03, 2018
USD ($)
Sep. 30, 2019
USD ($)
$ / shares
Sep. 30, 2018
USD ($)
Sep. 30, 2019
USD ($)
item
$ / shares
Sep. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
Class of Stock [Line Items]            
Shares Amount   $ 959,750,000   $ 959,750,000   $ 959,750,000
Distributions to preferred shareholders   $ 13,000,000.0 $ 13,000,000.0 $ 38,877,000 $ 39,614,000  
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    
Redeemable preferred stock, redemption price per share | $ / shares   $ 25.00   $ 25.00    
Series T Preferred Stock [Member]            
Class of Stock [Line Items]            
Cumulative preferred stock, dividend rate 6.00%          
Shares Amount $ 130,000,000.0