Contract assets and liabilities (Details 2) ¥ in Thousands, $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2024 CNY (¥)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 CNY (¥)
Contract assets \| $	$ 135		$ 66
Contract liabilities: deferred revenue \| $	(593)		(650)
Net contract (liabilities) / assets \| $	$ (458)		$ (584)
ZHEJIANG TIANLAN
Contract assets \| ¥		¥ 66,644		¥ 72,880
Contract liabilities: deferred revenue \| ¥		(35,367)		(43,452)
Net contract (liabilities) / assets \| ¥		¥ 31,277		¥ 29,428

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

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