Unaudited Condensed Consolidated Statement of Changes in Stockholders' Equity (Deficit) - USD ($)
$ in Thousands
Total
Common stock
Additional Paid-in Capital
(Accumulated deficit) retained earnings
Accumulated other comprehensive loss
Common shares outstanding at Dec. 31, 2012   195,463,955      
Stockholders' Equity (Deficit) at Dec. 31, 2012 $ (270,868) $ 1,954 $ 52,282 $ (327,104)  
Other comprehensive income 0        
Exercise of stock options (shares)   256,939      
Exercise of stock options 127 $ 3 124    
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition 1,420   1,420    
Net income 78,236     78,236  
Common shares outstanding at Dec. 31, 2013   195,720,894      
Stockholders' Equity (Deficit) at Dec. 31, 2013 (191,085) $ 1,957 55,826 (248,868)  
Other comprehensive income 0        
Exercise of stock options (shares)   22,260      
Exercise of stock options 37   37    
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition 1,820   1,820    
Net income $ 101,931     101,931  
Common shares outstanding at Dec. 31, 2014 195,743,154 195,743,154      
Stockholders' Equity (Deficit) at Dec. 31, 2014 $ (87,297) $ 1,957 57,683 (146,937)  
Other comprehensive income $ (31)       $ (31)
Exercise of stock options (shares) 396,010 396,010      
Exercise of stock options $ 2,251 $ 5 2,246    
Income tax benefit from exercise of stock options 1,536   1,536    
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures   46,750      
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures 935   935    
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures   30,682      
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures 614   614    
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition 1,885   1,885    
Net income $ 89,388     89,388  
Common shares outstanding at Dec. 31, 2015 196,216,596 196,216,596      
Stockholders' Equity (Deficit) at Dec. 31, 2015 $ 9,281 $ 1,962 64,899 (57,549) (31)
Other comprehensive income $ 28       28
Exercise of stock options (shares) 4,700 4,700      
Exercise of stock options $ 61   61    
Income tax benefit from exercise of stock options 3   3    
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition 447   447    
Net income $ 37,333     37,333  
Common shares outstanding at Mar. 31, 2016 196,221,296 196,221,296      
Stockholders' Equity (Deficit) at Mar. 31, 2016 $ 47,153 $ 1,962 $ 65,410 $ (20,216) $ (3)