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Related Parties - Additional Information (Detail) - USD ($)
$ in Thousands
1 Months Ended 3 Months Ended
Apr. 30, 2016
Mar. 31, 2017
Related Party Transaction [Line Items]    
Percentage of indirect ownership by principal stockholder 15.00%  
Treasury And Custodial Services Agreements    
Related Party Transaction [Line Items]    
Fees for related party services   $ 42