Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.2
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, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Concentration Risk [Line Items]        
Percentage of total production 41.70% 39.90% 41.10% 43.20%
Manufacturer One [Member]        
Concentration Risk [Line Items]        
Percentage of total production 15.40% 11.20% 15.80% 12.10%
Manufacturer Two [Member]        
Concentration Risk [Line Items]        
Percentage of total production 8.30% 9.00% 8.80% 11.50%
Manufacturer Three [Member]        
Concentration Risk [Line Items]        
Percentage of total production 7.00% 8.80% 6.60% 8.70%
Manufacturer Four [Member]        
Concentration Risk [Line Items]        
Percentage of total production 5.70% 5.80% 5.00% 5.90%
Manufacturer Five [Member]        
Concentration Risk [Line Items]        
Percentage of total production 5.30% 5.10% 4.90% 5.00%