Quarterly report pursuant to Section 13 or 15(d)

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)

v3.8.0.1
CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Stockholders' Equity    
Preferred stock par value per share (in usd per share) $ 0.01 $ 0.01
Preferred shares authorized (in shares) 50,000,000 50,000,000
Common stock par value per share (in usd per share) $ 0.01 $ 0.01
Common shares authorized (in shares) 450,000,000 450,000,000
Common shares issued (in shares) 175,434,778 174,496,587
Common shares outstanding (in shares) 175,434,778 174,496,587
Series A Preferred Stock [Member]    
Stockholders' Equity    
Preferred stock par value per share (in usd per share) $ 0.01  
Preferred stock dividend rate 8.125%  
Preferred shares issued (in shares) 5,750,000 5,750,000
Preferred shares outstanding (in shares) 5,750,000 5,750,000
Preferred stock liquidation preference $ 143,750 $ 143,750
Series B Preferred Stock [Member]    
Stockholders' Equity    
Preferred stock par value per share (in usd per share) $ 0.01  
Preferred stock dividend rate 7.625%  
Preferred shares issued (in shares) 11,500,000 11,500,000
Preferred shares outstanding (in shares) 11,500,000 11,500,000
Preferred stock liquidation preference $ 287,500 $ 287,500
Series C Preferred Stock [Member]    
Stockholders' Equity    
Preferred stock par value per share (in usd per share) $ 0.01  
Preferred stock dividend rate 7.25%  
Preferred shares issued (in shares) 11,800,000 11,800,000
Preferred shares outstanding (in shares) 11,800,000 11,800,000
Preferred stock liquidation preference $ 295,000 $ 295,000