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Fair Value Measurements - Additional Information (Detail) - USD ($)
12 Months Ended
Oct. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
Nov. 24, 2017
Derivatives, Fair Value [Line Items]        
Fair value of fixed-rate debt   $ 0    
Amount of interest rate swap     $ 150,000,000  
Locked interest rate     6.466%  
Derivative maturity date     Dec. 31, 2018  
Interest rate       50.00%
Cash payments related to the interest rate swap $ 1,300,000   $ 300,000  
Interest rate swaps outstanding   0    
Net hedging losses on the interest rate swaps   1,400,000 1,400,000  
Derivative in Net liability position   150,000,000    
Interest rate swap settlements in derivative loss (gain)     $ (609,000)  
Accumulated Other Comprehensive Income (loss) [Member]        
Derivatives, Fair Value [Line Items]        
Gain or loss related to interest rate swaps   $ 0    
Minimum [Member] | Senior Secured Term Loan B [Member]        
Derivatives, Fair Value [Line Items]        
Interest rate   0.75%    
Minimum [Member] | Senior Secured Term Loan B [Member] | London Interbank Offered Rate (LIBOR) [Member]        
Derivatives, Fair Value [Line Items]        
Interest rate     0.75%  
Maximum [Member] | Senior Secured Term Loan B [Member] | London Interbank Offered Rate (LIBOR) [Member]        
Derivatives, Fair Value [Line Items]        
Interest rate     1.00%