Annual report pursuant to Section 13 and 15(d)

SHAREHOLDERS' EQUITY - Preferred Stock Issued and Outstanding (Details)

v3.6.0.2
SHAREHOLDERS' EQUITY - Preferred Stock Issued and Outstanding (Details)
 3 Months Ended 6 Months Ended 12 Months Ended
Aug. 16, 2016
USD ($)
$ / shares
Mar. 14, 2016
USD ($)
$ / shares
Dec. 31, 2016
USD ($)
shares
Mar. 31, 2012
Jun. 30, 2016
USD ($)
shares
Dec. 31, 2016
USD ($)
shares
Dec. 31, 2008
$ / shares
shares
May 05, 2016
USD ($)
Dec. 31, 2015
shares
Class of Stock [Line Items]                  
Preferred Stock, Shares Outstanding | shares     1,098,006     1,098,006     398,006
Preferred Stock, Value, Outstanding | $     $ 1,071,227,000     $ 1,071,227,000      
Stock issued value | $           $ 584,936,000      
Depositary Shares, Issued | shares         24,000,000        
Series A Preferred Stock                  
Class of Stock [Line Items]                  
Preferred Stock, Shares Outstanding | shares     362,506     362,506      
Preferred Stock, Value, Outstanding | $     $ 362,506,000     $ 362,506,000      
Preferred stock, dividend percentage           .0850      
Number of shares issued for each share of convertible preferred stock | shares             83.668    
Conversion price (in dollars per share) | $ / shares             $ 11.95    
Convertible preferred stock, threshold percentage of stock price trigger             130.00%    
Convertible preferred stock, threshold consecutive trading days             30 days    
Convertible preferred stock, shares converted | shares     1            
Series B Preferred Stock                  
Class of Stock [Line Items]                  
Preferred Stock, Shares Outstanding | shares     35,500     35,500      
Preferred Stock, Value, Outstanding | $     $ 23,785,000     $ 23,785,000      
Preferred stock, dividend percentage           3-mo. LIBOR + 270 bps      
Preferred Stock, Redemption Date           Jan. 15, 2017      
Depository share, percent interest in preferred stock       0.025          
Series D Preferred Stock                  
Class of Stock [Line Items]                  
Preferred Stock, Shares Outstanding | shares     400,000     400,000      
Preferred Stock, Value, Outstanding | $     $ 386,348,000     $ 386,348,000      
Stock issued value | $           $ 584,936,000      
Preferred stock, dividend percentage           .0625      
Preferred Stock, Redemption Date           Jul. 15, 2021      
Preferred Stock, Par or Stated Value Per Share | $ / shares   $ 0.01              
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares   1,000              
Depositary Shares, Liquidation Preference Per Share | $ / shares   $ 25              
Payments of Stock Issuance Costs | $         $ 15,000,000        
Preferred Stock, Redemption Period   90 days              
Preferred Stock, Value, Issued | $ $ 100,000,000 $ 400,000,000           $ 200,000,000  
Depositary Shares, Issued | shares         4,000,000        
Preferred Stock, Dividend Rate, Percentage         6.25%        
Series D Preferred Stock2                  
Class of Stock [Line Items]                  
Preferred Stock, Shares Outstanding | shares     200,000     200,000      
Preferred Stock, Value, Outstanding | $     $ 198,588,000     $ 198,588,000      
Series C Preferred Stock                  
Class of Stock [Line Items]                  
Preferred Stock, Shares Outstanding | shares     100,000     100,000      
Preferred Stock, Value, Outstanding | $     $ 100,000,000     $ 100,000,000      
Preferred stock, dividend percentage           .05875      
Preferred Stock, Redemption Date           Jan. 15, 2022      
Preferred Stock, Par or Stated Value Per Share | $ / shares $ 0.01                
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares 1,000                
Depositary Shares, Liquidation Preference Per Share | $ / shares $ 25                
Preferred Stock, Redemption Period 90 days                
Preferred Stock, Dividend Rate, Percentage         5.875%