Preferred and Common Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 6 Months Ended 11 Months Ended
Jan. 28, 2014
Jun. 30, 2015
Jul. 08, 2014
Jun. 30, 2014
Dec. 15, 2014
Dec. 31, 2014
Exercised number of shares   0   141,839    
Total amount of shares issued   $ 0   $ 638    
Number of restricted common stock issued to employees         1,151,052  
Vested restricted stock units   15,000   25,120    
Forfeited restricted shares   2,223   4,625    
Preferred stock shares outstanding   74,229       75,069
Common stock shares outstanding   107,835,547       105,831,718
Preferred units conversion price   $ 10        
Common stock issued upon conversion   840,000        
Conversion terms of preferred stock   The shares of convertible preferred stock were converted pursuant to their original terms, which provided that five years after the issuance date of the convertible preferred stock, 30% of the then-outstanding shares of preferred stock shall automatically convert into shares of common stock determined by dividing the amount of the liquidation preference ($10,000 per share) by a conversion price equal to $10.00 per share of common stock.        
American Depositary Shares            
Sale of stock - Redemption terms   Each of the shares represents 1/100th of a share of the Series G and H, with a liquidation preference of $2,500.00 per share ($25.00 per American Depositary Share). Dividends are payable quarterly in arrears on the Series G at a rate of 8.75% per annum and on the Series H at a rate of 8.625% per annum of the stated liquidation preference. The Company has accounted for these shares as equity.        
American Depositary Shares - Series G            
Preferred stock shares outstanding   20,000       20,000
Number of shares 2,000,000          
Sale of stock - Redemption price per share $ 2,500          
Preferred stock dividend rate percentage 8.75%          
Sale of stock - Net proceeds $ 47,846          
American Depositary Shares - Series H            
Preferred stock shares outstanding   48,000       48,000
Number of shares     4,800,000      
Sale of stock - Redemption price per share     $ 2,500      
Preferred stock dividend rate percentage     8.625%      
Sale of stock - Net proceeds     $ 115,756      
Convertible preferred stock            
Preferred stock shares outstanding   6,229       7,069
Preferred stock converted into common shares   840