Acquisition and Investment - ASV Stock Purchase - Schedule of Restated Purchase Price Allocations (Detail) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Jan. 15, 2015
Dec. 31, 2014
Dec. 19, 2014
Schedule Of Business Acquisitions Purchase Price Allocation [Line Items]          
Goodwill $ 70,248 $ 71,337 $ 30,173 $ 43,741  
ASV Inc [Member]          
Schedule Of Business Acquisitions Purchase Price Allocation [Line Items]          
Goodwill $ 30,579       $ 30,579
Inventory         26,757
Fixed assets         18,915
Accrued expenses         $ (7,357)
ASV Inc [Member] | Provisional Amount [Member]          
Schedule Of Business Acquisitions Purchase Price Allocation [Line Items]          
Goodwill       26,744  
Inventory       27,217  
Fixed assets       19,177  
Accrued expenses       (3,975)  
Income tax payable on conversion of ASV       (16,500)  
ASV Inc [Member] | Adjustment Based On Review Of Purchase Price Allocation          
Schedule Of Business Acquisitions Purchase Price Allocation [Line Items]          
Goodwill       3,835  
Inventory       (460)  
Fixed assets       (262)  
Accrued expenses       (3,382)  
Income tax payable on conversion of ASV       269  
ASV Inc [Member] | Revised Amount [Member]          
Schedule Of Business Acquisitions Purchase Price Allocation [Line Items]          
Goodwill       30,579  
Inventory       26,757  
Fixed assets       18,915  
Accrued expenses       (7,357)  
Income tax payable on conversion of ASV       $ (16,231)