Selling expenses (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Selling expenses [Abstract]

Disclosure of detailed information about selling expenses [text block]

Amounts in US$ '000	2017		2016		2015
Transportation		864		3,559		4,760
Selling taxes and other		272		663		451
		1,136		4,222		5,211