Quarterly report pursuant to Section 13 or 15(d)

Business and Credit Concentrations - Company's Top Five Manufacturers Produced (Detail)

v3.7.0.1
Business and Credit Concentrations - Company's Top Five Manufacturers Produced (Detail) - Cost of Goods, Total [Member] - Supplier Concentration Risk [Member]
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Concentration Risk [Line Items]        
Percentage of total production 51.60% 56.00% 51.70% 55.50%
Manufacturer One [Member]        
Concentration Risk [Line Items]        
Percentage of total production 20.00% 25.10% 21.10% 25.60%
Manufacturer Two [Member]        
Concentration Risk [Line Items]        
Percentage of total production 11.00% 10.40% 11.00% 10.70%
Manufacturer Three [Member]        
Concentration Risk [Line Items]        
Percentage of total production 8.10% 8.90% 8.60% 9.60%
Manufacturer Four [Member]        
Concentration Risk [Line Items]        
Percentage of total production 6.30% 6.60% 6.00% 5.40%
Manufacturer Five [Member]        
Concentration Risk [Line Items]        
Percentage of total production 6.20% 5.00% 5.00% 4.20%