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EMPLOYEE BENEFIT PLANS - Narrative (Detail) - USD ($)
shares in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Employee Stock Purchase Plan [Line Items]      
Maximum matching contribution per dollar per employee contribution $ 0.50    
Maximum match per employee per calendar year $ 1,000    
Employer contributions vesting period 3 years    
Employer contributions $ 1,187,000 $ 1,119,000 $ 1,033,000
Class A Common Stock      
Employee Stock Purchase Plan [Line Items]      
Discount rate 15.00%    
Stock issued under stock purchase plan (in shares) 41 70 80
Stock available for distribution under stock purchase plan (in shares) 143