Land use right, net (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ZHEJIANG TIANLAN
Land use right	¥ 7,361	¥ 7,361
Less: Accumulated amortisation	(1,763)	(1,614)
Net	5,598	5,747
Amortisation expense	149	149	¥ 149
ZHEJIANG JIAHUAN
Land use right	7,987	7,987
Less: Accumulated amortisation	(1,862)	(1,699)
Net	6,125	6,288
Amortisation expense	¥ 163	¥ 163	¥ 163

Gross carrying amount before accumulated amortization as of the balance sheet date of an intangible asset that arises from a contractual arrangement with a third party (not including franchise rights and license agreements).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

Name:	us-gaap_FiniteLivedContractualRightsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant