Contract assets and liabilities (Details 2) ¥ in Thousands, $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2023 CNY (¥)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 CNY (¥)
Contract assets \| $	$ 66		$ 217
Contract liabilities: deferred revenue \| $	(650)		(625)
Net contract (liabilities) / assets \| $	$ (584)		$ (408)
ZHEJIANG TIANLAN
Contract assets \| ¥		¥ 72,880		¥ 76,992
Contract liabilities: deferred revenue \| ¥		(43,452)		(34,503)
Net contract (liabilities) / assets \| ¥		¥ 29,428		¥ 42,489

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479837/606-10-45-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479837/606-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-8

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