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The Company - Additional Information (Detail)
 12 Months Ended
Dec. 22, 2016
USD ($)
Dec. 31, 2017
USD ($)
Segment
Dec. 31, 2016
USD ($)
Disclosure Company Additional Information [Abstract]      
Subscription agreement date   Dec. 22, 2016  
Preferred stock purchased, value under subscription agreement $ 4,500,000    
Dividends paid   $ 0 $ 0
Amount paid withholding taxes in Canadian Revenue Agency     7,600,000
Income tax expense related to intercompany dividends     2,500,000
Accrued one-time income tax payment     $ 32,600,000
Number of reportable segments | Segment   2