Quarterly report pursuant to Section 13 or 15(d)

Contingencies - Additional Information (Detail)

v3.8.0.1
Contingencies - Additional Information (Detail) - USD ($)
 9 Months Ended
Sep. 30, 2017
Dec. 31, 2016
Contingencies And Commitments [Line Items]    
Maximum exposure associated with general indemnifications $ 500,000 $ 500,000
General indemnifications minimum expiration period 1 year  
General indemnifications maximum expiration period 3 years  
Contingent liability reserve balance after reduction $ 2,800,000 $ 2,800,000
Acquired business, earnings targets, maximum term 10 years  
Maximum aggregate earnout payment $ 80,000,000  
Dealership [Member]    
Contingencies And Commitments [Line Items]    
Joint venture ownership percentage 50.00% 50.00%
Other Accrued Liabilities [Member]    
Contingencies And Commitments [Line Items]    
Amount reserved for pending proceedings $ 3,000,000 $ 300,000
Other Long-Term Liabilities [Member]    
Contingencies And Commitments [Line Items]    
Amount reserved for pending proceedings $ 200,000 $ 200,000