Quarterly report pursuant to Section 13 or 15(d)

SUBSEQUENT EVENTS (Details)

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SUBSEQUENT EVENTS (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 9 Months Ended 12 Months Ended
Oct. 31, 2017
Oct. 04, 2017
Aug. 01, 2017
May 04, 2017
Feb. 27, 2017
May 31, 2017
Jan. 31, 2017
Sep. 30, 2017
Dec. 31, 2016
Subsequent Event [Line Items]                  
Dividends declared               $ 4,185  
Series B preferred stock                  
Subsequent Event [Line Items]                  
Dividends declared per share of preferred stock (in dollars per share)     $ 0.609375 $ 0.609375 $ 0.609375        
Preferred stock, dividend rate (as percent)     9.75% 9.75% 9.75%     9.75% 9.75%
Series C preferred stock                  
Subsequent Event [Line Items]                  
Dividends declared per share of preferred stock (in dollars per share)     $ 0.503125 $ 0.503125 $ 0.503125        
Preferred stock, dividend rate (as percent)     8.05% 8.05% 8.05%     8.05% 8.05%
Series D preferred stock                  
Subsequent Event [Line Items]                  
Dividends declared per share of preferred stock (in dollars per share)     $ 0.523438 $ 0.523438 $ 0.523438        
Preferred stock, dividend rate (as percent)     8.375% 8.375% 8.375%     8.375% 8.375%
Issued to the independent directors                  
Subsequent Event [Line Items]                  
Shares issued to independent directors (in shares)           90,366 18,074    
Subsequent event                  
Subsequent Event [Line Items]                  
Dividends declared $ 1,400                
Subsequent event | Series B preferred stock                  
Subsequent Event [Line Items]                  
Dividends declared per share of preferred stock (in dollars per share) $ 0.609375                
Preferred stock, dividend rate (as percent) 9.75%                
Subsequent event | Series C preferred stock                  
Subsequent Event [Line Items]                  
Dividends declared per share of preferred stock (in dollars per share) $ 0.503125                
Preferred stock, dividend rate (as percent) 8.05%                
Subsequent event | Series D preferred stock                  
Subsequent Event [Line Items]                  
Dividends declared per share of preferred stock (in dollars per share) $ 0.523438                
Preferred stock, dividend rate (as percent) 8.375%                
Subsequent event | Issued to the independent directors | Common Stock                  
Subsequent Event [Line Items]                  
Shares issued to independent directors (in shares)   30,822