Name:	grst_NetOperatingLossesOne
Namespace Prefix:	grst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-2

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains in other comprehensive income.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-8

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Amount of deferred tax liability attributable to taxable temporary differences from long-lived assets other than property, plant, and equipment.

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- References

No definition available.