Annual report pursuant to Section 13 and 15(d)

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

v3.19.3.a.u2
Business and Credit Concentrations - Company's Top Five Manufacturers Produced (Detail) - Cost of Goods, Total [Member] - Supplier Concentration Risk [Member]
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Concentration Risk [Line Items]      
Percentage of total production 40.60% 41.90% 47.50%
Manufacturer One [Member]      
Concentration Risk [Line Items]      
Percentage of total production 16.00% 12.80% 17.90%
Manufacturer Two [Member]      
Concentration Risk [Line Items]      
Percentage of total production 7.30% 10.10% 11.10%
Manufacturer Three [Member]      
Concentration Risk [Line Items]      
Percentage of total production 7.20% 8.60% 8.80%
Manufacturer Four [Member]      
Concentration Risk [Line Items]      
Percentage of total production 5.10% 5.40% 5.40%
Manufacturer Five [Member]      
Concentration Risk [Line Items]      
Percentage of total production 5.00% 5.00% 4.30%