Revolving Term Credit Facilities and Debt - Additional Information - ASV Loan Facilities (Detail) - USD ($)
Dec. 23, 2016
Dec. 31, 2016
Line of Credit Facility [Line Items]    
Term loan facility   $ 133,916,000
ASV Loan Facilities [Member]    
Line of Credit Facility [Line Items]    
Maximum borrowing capacity $ 65,000,000  
Credit agreement, expiration period 5 years  
ASV Loan Facilities [Member] | Revolving Credit Facility [Member]    
Line of Credit Facility [Line Items]    
Maximum borrowing capacity $ 35,000,000  
ASV Loan Facilities [Member] | Term Loan A [Member]    
Line of Credit Facility [Line Items]    
Term loan facility 8,500,000  
ASV Loan Facilities [Member] | Term Loan B [Member]    
Line of Credit Facility [Line Items]    
Term loan facility $ 21,500,000