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Fair Value Measurements (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 1991
Apr. 18, 2017
Public Preferred Stock [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Abstract]        
Preferred stock dividend rate per annum 12.00% 12.00% 6.00%  
Public preferred stock par value (in dollar per share)   $ 0.01    
Carrying value of public preferred stock   $ 139.2    
Senior Redeemable Preferred Stock [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Abstract]        
Redemption amount of senior redeemable preferred stock       $ 2.1
Preferred stock dividend rate per annum 14.125%      
Estimate of Fair Value, Fair Value Disclosure [Member] | Public Preferred Stock [Member]        
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Abstract]        
Public preferred stock   $ 60.5