Summary of significant accounting policies - Schedule of Useful Lives (Detail)
|
12 Months Ended |
---|---|
Dec. 31, 2012
|
|
Buildings [Member] | Minimum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 25 years |
Buildings [Member] | Maximum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 33 years |
Plant and equipment [Member] | Minimum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 2 years |
Plant and equipment [Member] | Maximum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 10 years |
Furniture and fixtures [Member] | Minimum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 4 years |
Furniture and fixtures [Member] | Maximum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 8 years |
Instrumentation [Member] | Minimum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 3 years |
Instrumentation [Member] | Maximum [Member]
|
|
Foreign Currency Translation [Line Items] | |
Useful life, in years | 4 years |