Contract assets and liabilities (Details 2)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 CNY (¥)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 CNY (¥)
Contract assets: unbilled revenue \| $	$ 217,000		$ 74,000
Contract liabilities: deferred revenue \| $	(625)		(1,076)
Net contract (liabilities) / assets \| $	$ (408,000)		$ (1,002,000)
ZHEJIANG TIANLAN
Contract assets: unbilled revenue \| ¥		¥ 76,992,000		¥ 72,310,000
Contract liabilities: deferred revenue \| ¥		(34,503)		(37,481,000)
Net contract (liabilities) / assets \| ¥		¥ 42,489,000		¥ 34,829,000

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130549-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130531-203044

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=126919976&loc=SL49130533-203044

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant