v2.4.1.9
Accounts receivable, trade (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Accounts receivable, trade [Abstract]      
Accounts receivable $ 910us-gaap_AccountsReceivableGrossCurrent $ 48,161us-gaap_AccountsReceivableGrossCurrent  
Allowance for doubtful accounts    (98)us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent  
Accounts receivable, net 910us-gaap_AccountsReceivableNetCurrent 48,063us-gaap_AccountsReceivableNetCurrent  
Balance at the beginning of the year 98us-gaap_AllowanceForDoubtfulAccountsReceivable     
Addition    98us-gaap_ProvisionForDoubtfulAccounts   
Disposal of a subsidiary (98)us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs     
Balance at the end of the year    $ 98us-gaap_AllowanceForDoubtfulAccountsReceivable