Selling expenses (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Selling expenses [Abstract]

Disclosure of detailed information about selling expenses [text block]

Amounts in US$ '000	2018		2017		2016
Transportation		2,638		864		3,559
Selling taxes and other		1,385		272		663
		4,023		1,136		4,222