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6. Accounts receivable (Detail)	Dec. 31, 2012	Dec. 31, 2011
RevenueOfConsolidatedSales	35.00%	70.00%

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- Definition

No authoritative reference available.

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No definition available.

+ Details

Name:	grst_RevenueOfConsolidatedSales
Namespace Prefix:	grst_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant