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Related Party Transactions - Additional Information (Details) - LTRIP - USD ($)
shares in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Related Party Transaction [Line Items]    
Beneficially ownership of shares of common stock 18.2  
Percentage taken from outstanding shares of common stock 14.30%  
Percentage of beneficially ownership of shares of common stock class B 22.20%  
Right to voting one vote per share  
Beneficially ownership of equity securities 57.40%  
Related party transactions $ 0 $ 0
Class B Common Stock    
Related Party Transaction [Line Items]    
Beneficially ownership of shares of common stock 12.8  
Percentage taken from outstanding shares of common stock 100.00%  
Right to voting Ten votes per share