Property, plant and equipment (Schedule of Property, Plant and Equipment) (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property and equipment	$ 157,841,838	$ 138,917,563
Less accumulated depreciation and amortization	(30,499,600)	(24,266,456)
Property, plant, and equipment, net	127,342,238	114,651,107
Land Use Rights [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	9,867,084	2,358,862
Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	31,688,077	11,145,342
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	111,938,773	122,844,563
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	425,514	233,217
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 3,922,390	$ 2,335,579

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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