XML 81 R57.htm IDEA: XBRL DOCUMENT v3.8.0.1
Accounts Payable - Inventory Financing Facility - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Accounts Payable And Accrued Expenses [Line Items]      
Inventory financing facility maximum borrowing capacity $ 325,000,000    
Inventory financing facility maturity date Jun. 23, 2021    
Imputed interest on inventory financing facility $ 6,736,000 $ 3,385,000 $ 3,406,000
Inventory financing facility interest rate if balances are not paid within stated vendor terms Prime plus 1.25%    
Inventory financing facility rate if vendor terms not met equal prime plus 1.25%    
Maximum [Member]      
Accounts Payable And Accrued Expenses [Line Items]      
Inventory financing facility additional borrowing capacity $ 25,000,000