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Income taxes (Details 11)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Threshold of likelihood of tax positions being realized upon ultimate settlement with a taxing authority	50.00%

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- Definition

Threshold of likelihood that tax benefits will be realized upon ultimate settlement with a taxing authority.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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