Summary of Significant Accounting Policies (Details)	12 Months Ended
Dec. 31, 2014
Basis of Presentation
Ownership interest in subsidiaries (as a percent)	100.00%snh_OwnershipPercentageHeldInSubsidiary
Buildings and improvements \| Real Estate Investment [Member]
Real Estate Properties
Estimated useful lives	40 years
Furniture and Fixtures [Member] \| Real Estate Investment [Member] \| Minimum
Real Estate Properties
Estimated useful lives	7 years
Furniture and Fixtures [Member] \| Real Estate Investment [Member] \| Maximum
Real Estate Properties
Estimated useful lives	12 years

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration