Preferred and Common Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
 2 Months Ended 4 Months Ended 6 Months Ended 10 Months Ended 11 Months Ended 12 Months Ended
Feb. 29, 2016
Apr. 19, 2017
Jul. 15, 2017
Nov. 08, 2016
Dec. 11, 2017
Dec. 11, 2015
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Preferred stock shares outstanding             46,302 49,504            
Common stock shares outstanding             120,386,472 117,131,407            
Acquisition of treasury stock, value               $ 818 $ 252          
Value of the exchange offer             $ 12 12            
Amount of tender offer paid in cash             (571) (9,323)            
Payments for tender offer expenses             571 9,323 $ 0          
Shares tendered, nominal value             $ 0 $ 0            
Dividend rate of preferred stock             2.00%              
Dividends undeclared                            
Dividends cancelled             $ 702              
Restricted common stock                            
Number of common stock issued to employees           2,540,000                
Forfeited shares of common stock             4,232 2,908            
Restricted stock units                            
Vested stock units             843,332 24,970 16,960          
Stock options                            
Exercised number of shares             0 0 0 143,189 153,556 29,251 130,578 130,577
Restricted stock units granted           1,000,000                
Series G | ADS Exchange Offer                            
Number of shares issued for the exchange offer   360   5,449                    
Series H | ADS Exchange Offer                            
Number of shares issued for the exchange offer   406   18,982                    
Series G and Series H                            
Percentage of the increase of the preferred dividend rate     0.25%                      
Series G and Series H | ADS Exchange Offer                            
Tender offer, stocks       7,589,176                    
Shares exchanged aggregate book value       $ 61,078                    
Payments for tender offer expenses   $ 571   9,323                    
Shares tendered, nominal value   1,843                        
Fair value of stock issued       $ 7,893                    
Series G and Series H | Dividends undeclared | ADS Exchange Offer                            
Dividends cancelled   $ 270                        
American Depositary Shares - The Series G                            
Preferred stock shares outstanding             14,191 14,551            
Sale of Stock- Redemption price per share             $ 25              
Number of shares             2,000,000              
Preferred Stock, Liquidation Preference Per Share             $ 2,500              
Dividend rate of preferred stock             8.75%              
American Depositary Shares - The Series H                            
Preferred stock shares outstanding             28,612 29,018            
Sale of Stock- Redemption price per share             $ 25              
Number of shares             4,800,000              
Preferred Stock, Liquidation Preference Per Share             $ 2,500              
Dividend rate of preferred stock             8.625%              
Convertible preferred stock                            
Conversion of Stock, Shares converted             2,436              
Preferred stock shares outstanding             3,499 5,935            
Sale of Stock- Redemption price per share             $ 14              
Preferred stock liquidation preference             $ 10,000              
Common Stock                            
Number of common stock issued to employees         4,320,975                  
Converted Shares of Common Stock             1,790,150   1,134,000          
Acquisition of treasury stock, shares               948,584 199,324          
Amount of tender offer paid in cash               $ 1            
Tender offer, stocks             625,815 7,589,176            
Common Stock | ADS Exchange Offer                            
Tender offer, stocks   625,815                        
Fair value of stock issued   $ 1,127                        
Common Stock | First conversion                            
Converted Shares of Common Stock             1,740,000              
Common Stock | Second conversion                            
Converted Shares of Common Stock             50,150              
Fair value of stock issued             $ 84              
Preferred Stock                            
Conversion of Stock, Shares converted             2,436   1,134          
Number of shares issued for the exchange offer             766 24,431            
Preferred Stock | Dividends undeclared                            
Undeclared preferred dividends             $ 19,693              
Dividends cancelled             972              
Share Repurchase Program | Common Stock                            
Share repurchase program, Authorized amount             $ 25,000              
Acquisition of treasury stock, shares 1,147,908             948,584            
Acquisition of treasury stock, value $ 1,070             $ 818