v3.3.1.900
STOCKHOLDERS EQUITY (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 4 Months Ended 8 Months Ended 12 Months Ended
Nov. 30, 2014
$ / shares
shares
Apr. 30, 2014
shares
Apr. 21, 2014
shares
Dec. 31, 2014
shares
Dec. 31, 2015
USD ($)
shares
STOCKHOLDERS EQUITY          
Treasury stock shares acquired (in shares)         263,622
Treasury stock shares acquired | $         $ 7,616
Group LP          
STOCKHOLDERS EQUITY          
Number of units held by noncontrolling interest holders       34,479,961 33,803,921
Noncontrolling interests (as a percent)       64.00% 63.00%
Class A common stock          
STOCKHOLDERS EQUITY          
Aggregate stock issuance (in shares)   15,263,653      
Reorganization of equity structure (in shares)   7,699,851 7,699,851    
Common Stock issued (in shares)       7,483,442  
Common Stock issued in connection with settlement of appreciation rights issued in prior years (in shares)   88,802      
Issuance of Class A common stock and acquisition of Class A partnership units in connection with secondary offering (in shares)       4,511,058  
Common stock, shares issued       19,770,893 20,536,740
Common stock, shares outstanding 19,770,893     19,770,893 20,273,118
Number of shares of common stock to be issued upon exchange of a partnership unit   1     1
Class A common stock | IPO          
STOCKHOLDERS EQUITY          
Common Stock issued (in shares)   7,475,000      
Class A common stock | Secondary Offering          
STOCKHOLDERS EQUITY          
Common Stock issued (in shares) 4,509,400        
Issuance of new and sale of existing common stock (in shares) 6,325,000        
Issuance of Class A common stock and acquisition of Class A partnership units in connection with secondary offering (in shares) 4,511,058        
Class A common stock | Group LP          
STOCKHOLDERS EQUITY          
Common stock, shares outstanding         20,273,118
Class B common stock          
STOCKHOLDERS EQUITY          
Common Stock issued (in shares)   36,158,698 36,158,698    
Issuance of Class A common stock and acquisition of Class A partnership units in connection with secondary offering (in shares)       (4,507,453)  
Common stock, shares issued       31,621,542 31,229,236
Common stock, shares outstanding       31,621,542 31,229,236
Ratio of subscription price to the initial public offering price of shares of common stock   0.00055      
Aggregate number of shares of Class B common stock that may be converted into Class A common stock   20,000      
Dividends payable ratio to outstanding shares of publicly traded common stock   0.00055      
Class B common stock | Secondary Offering          
STOCKHOLDERS EQUITY          
Issuance of Class A common stock and acquisition of Class A partnership units in connection with secondary offering (in shares) 4,507,453        
Shares converted 2,998,322        
Shares issued upon conversion 1,658        
Conversion ratio 0.00055        
Number of shares repurchased and retired 1,509,131        
Price per share of stock which was repurchased and retired | $ / shares $ 28        
Class B common stock | Maximum          
STOCKHOLDERS EQUITY          
Aggregate number of shares of Class B common stock that may be converted into Class A common stock   20,000