Annual report pursuant to Section 13 and 15(d)

Summary of significant accounting policies (Details)

v3.7.0.1
Summary of significant accounting policies (Details)
12 Months Ended
Dec. 31, 2016
Buildings [Member] | Minimum [Member]  
Property, Plant and Equipment [Line Items]  
Property, Plant and Equipment, Useful Life 20 years
Buildings [Member] | Maximum [Member]  
Property, Plant and Equipment [Line Items]  
Property, Plant and Equipment, Useful Life 40 years
Furniture, Fixtures and Office Equipment [Member]  
Property, Plant and Equipment [Line Items]  
Property, Plant and Equipment, Useful Life 5 years
Leasehold Improvement [Member]  
Property, Plant and Equipment [Line Items]  
Property, Plant and Equipment, Estimated Useful Lives Shorter of the remaining lease terms or estimated useful lives
Machinery and Equipment [Member]  
Property, Plant and Equipment [Line Items]  
Property, Plant and Equipment, Useful Life 10 years
Motor Vehicles [Member]  
Property, Plant and Equipment [Line Items]  
Property, Plant and Equipment, Useful Life 5 years