22. Segment information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue
Trading and manufacturing	$ 11,647	$ 10,986	$ 10,866
Engineering	7,175us-gaap_TechnologyServicesRevenue	7,616us-gaap_TechnologyServicesRevenue	10,779us-gaap_TechnologyServicesRevenue
Revenue	18,822us-gaap_Revenues	18,602us-gaap_Revenues	21,645us-gaap_Revenues
Operating (loss)/income
Trading and manufacturing	(214)CLWT_ExpenseTradingAndManufacturing	(241)CLWT_ExpenseTradingAndManufacturing	(301)CLWT_ExpenseTradingAndManufacturing
Engineering	(640)us-gaap_TechnologyServicesCosts	106us-gaap_TechnologyServicesCosts	401us-gaap_TechnologyServicesCosts
Unallocated corporate expenses	(117)	(120)	(159)
Operating expenses	(971)us-gaap_OperatingIncomeLoss	(255)us-gaap_OperatingIncomeLoss	(59)us-gaap_OperatingIncomeLoss
Depreciation:
Trading and manufacturing	67us-gaap_CostOfGoodsSoldDepreciation	74us-gaap_CostOfGoodsSoldDepreciation	88us-gaap_CostOfGoodsSoldDepreciation
Engineering	21	34	42
Depreciation	88us-gaap_Depreciation	108us-gaap_Depreciation	130us-gaap_Depreciation
Capital Expenditures, Gross
Trading and manufacturing	2	31	12
Engineering	8CLWT_CapitalExpendiruresEngineering	20CLWT_CapitalExpendiruresEngineering	29CLWT_CapitalExpendiruresEngineering
Total	10CLWT_TotalCapitalExpendirures	51CLWT_TotalCapitalExpendirures	41CLWT_TotalCapitalExpendirures
Assets
Trading and manufacturing	5,664CLWT_TradingAndManufacturingAssets	5,067CLWT_TradingAndManufacturingAssets
Engineering	18,022CLWT_EngineeringAssets	18,811CLWT_EngineeringAssets
Total assets	23,686us-gaap_Assets	23,878us-gaap_Assets
Liabilities
Trading and manufacturing	2,929CLWT_TradingAndManufacturingLiabilities	1,334CLWT_TradingAndManufacturingLiabilities
Engineering	2,940CLWT_EngineeringLiabilities	4,667CLWT_EngineeringLiabilities
Total	$ 5,869us-gaap_Liabilities	$ 6,001us-gaap_Liabilities

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The expense recognized in the current period that allocates the cost of a tangible asset over the asset's useful life. This element applies only to an asset used in the production of goods sold.

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Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

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Revenue not otherwise defined in the taxonomy from the sale of manufactured products.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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