Income Taxes (Details) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($)
Income Tax Disclosure [Abstract]
Income tax expense relating to the business change	$ 282

Effective Income Tax Rate Reconciliation, Business Change, Amount

No definition available.

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Namespace Prefix:	sevn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration