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STOCK-BASED COMPENSATION AND EMPLOYEE BENEFIT PLANS - Summary of Service-Based Restricted Activity (Details) - Service-based Restricted Shares - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Service-based Restricted Shares      
Outstanding beginning of period (in shares) 633,451    
Granted (in shares) 292,448    
Vested (in shares) (268,352)    
Canceled (in shares) (47,661)    
Outstanding end of period (in shares) 609,886 633,451  
Expected to vest (in shares) 609,886    
Weighted Average Grant Date Fair Value      
Outstanding beginning of period (in usd per share) $ 17.89    
Granted (in usd per share) 21.46 $ 17.67 $ 16.69
Vested (in usd per share) 17.67    
Canceled (in usd per share) 19.20    
Outstanding end of period (in usd per share) 19.59 $ 17.89  
Expected to vest (in usd per share) $ 19.59