Reserves for Credit Losses - Additional Information (Detail) - customer |
9 Months Ended | |
|---|---|---|
Sep. 30, 2015 |
Sep. 30, 2014 |
|
| Concentration Risk [Line Items] | ||
| Trade receivable payments period | 30 days | |
| Days past due when receivables are generally written off | 150 days | |
| Percentage of trade accounts receivables less than 60 days past due | 98.00% | 99.00% |
| Customer Concentration Risk [Member] | Accounts Receivable [Member] | ||
| Concentration Risk [Line Items] | ||
| Concentration risk, number of customers | 0 |