9. Property, plant and equipment (Details 1) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 ZHEJIANG TIANLAN CNY	Dec. 31, 2013 ZHEJIANG TIANLAN CNY	Dec. 31, 2012 ZHEJIANG TIANLAN CNY	Dec. 31, 2014 ZHEJIANG JIAHUAN CNY	Dec. 31, 2013 ZHEJIANG JIAHUAN CNY	Dec. 31, 2012 ZHEJIANG JIAHUAN CNY
Depreciation charge	$ 88us-gaap_DepreciationAndAmortization	$ 108us-gaap_DepreciationAndAmortization	$ 130us-gaap_DepreciationAndAmortization	2,985	2,956	3,017	2,408	2,461	2,028

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Name:	us-gaap_DepreciationAndAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration