Annual report pursuant to Section 13 and 15(d)

SUBSEQUENT EVENTS (Details)

v3.8.0.1
SUBSEQUENT EVENTS (Details) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 12 Months Ended
Mar. 06, 2018
Mar. 31, 2007
Oct. 31, 2005
Mar. 31, 2003
Dec. 31, 2017
Dec. 31, 2016
Series B Cumulative Redeemable Preferred Stock            
Subsequent Event [Line Items]            
Preferred stock, dividend rate (as percent)       9.75% 9.75% 9.75%
Series C Cumulative Redeemable Preferred Stock            
Subsequent Event [Line Items]            
Preferred stock, dividend rate (as percent)     8.05%   8.05% 8.05%
Series D Cumulative Redeemable Preferred Stock            
Subsequent Event [Line Items]            
Preferred stock, dividend rate (as percent)   8.375%     8.375% 8.375%
Subsequent Event            
Subsequent Event [Line Items]            
Dividends payable $ 1.4          
Subsequent Event | Series B Cumulative Redeemable Preferred Stock            
Subsequent Event [Line Items]            
Dividends declared (in dollars per share) $ 0.609375          
Preferred stock, dividend rate (as percent) 9.75%          
Subsequent Event | Series C Cumulative Redeemable Preferred Stock            
Subsequent Event [Line Items]            
Dividends declared (in dollars per share) $ 0.503125          
Preferred stock, dividend rate (as percent) 8.05%          
Subsequent Event | Series D Cumulative Redeemable Preferred Stock            
Subsequent Event [Line Items]            
Dividends declared (in dollars per share) $ 0.523438          
Preferred stock, dividend rate (as percent) 8.375%