Restricted cash (Tables)
|12 Months Ended|
Dec. 31, 2016
|Restricted cash [Abstract]|
|Schedule of Restricted Cash and Cash Equivalents [Table Text Block]||
Tabular disclosure of the cash and cash items which are restricted as to withdrawal or usage. The provisions of any restrictions are described in a note to the financial statements. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits.
Reference 1: http://www.xbrl.org/2003/role/presentationRef