4. Accounts Receivable (Tables)
|12 Months Ended|
Dec. 31, 2016
|Schedule of accounts receivable||
Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables.
Reference 1: http://www.xbrl.org/2003/role/presentationRef