EQUITY-BASED COMPENSATION - Summary of stock option and SAR activity (Details 1) - Stock Option And Stock Appreciation Rights - $ / shares
shares in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Shares      
Outstanding, January 1, 2016 1,529    
Granted 966    
Exercised (238) (56) (270)
Forfeited or expired (608)    
Outstanding, at December 31, 2016 1,649 1,529  
Exercisable at December 31, 2016 453    
Weighted Average Exercise Price      
Outstanding, January 1, 2015 $ 8.69    
Granted 7.11    
Exercised 4.32    
Forfeited or expired 9.77    
Outstanding, at December 31, 2016 7.97 $ 8.69  
Exercisable at December 31, 2016 $ 9.04