Annual report pursuant to Section 13 and 15(d)

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

v3.6.0.2
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, 2016
Dec. 31, 2015
Dec. 31, 2014
Concentration Risk [Line Items]      
Percentage of total production 51.00% 56.50% 58.90%
Manufacturer One [Member]      
Concentration Risk [Line Items]      
Percentage of total production 22.90% 31.50% 37.50%
Manufacturer Two [Member]      
Concentration Risk [Line Items]      
Percentage of total production 10.10% 9.10% 6.10%
Manufacturer Three [Member]      
Concentration Risk [Line Items]      
Percentage of total production 8.80% 7.30% 5.70%
Manufacturer Four [Member]      
Concentration Risk [Line Items]      
Percentage of total production 4.90% 5.00% 4.90%
Manufacturer Five [Member]      
Concentration Risk [Line Items]      
Percentage of total production 4.30% 3.60% 4.70%