Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Business and Credit Concentrations - Company's Top Five Manufacturers Produced (Detail) - Cost of Goods, Total [Member] - Supplier Concentration Risk [Member]
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Concentration Risk [Line Items]    
Percentage of total production 41.70% 48.30%
Manufacturer One [Member]    
Concentration Risk [Line Items]    
Percentage of total production 16.30% 15.50%
Manufacturer Two [Member]    
Concentration Risk [Line Items]    
Percentage of total production 9.30% 11.90%
Manufacturer Three [Member]    
Concentration Risk [Line Items]    
Percentage of total production 6.00% 8.60%
Manufacturer Four [Member]    
Concentration Risk [Line Items]    
Percentage of total production 5.10% 6.90%
Manufacturer Five [Member]    
Concentration Risk [Line Items]    
Percentage of total production 5.00% 5.40%