XML 33 R24.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Real Estate Properties (Details) (USD $) In Thousands, unless otherwise specified | 1 Months Ended | 3 Months Ended | 1 Months Ended | 12 Months Ended | 1 Months Ended | 0 Months Ended | 1 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Feb. 28, 2015 property | Mar. 31, 2015 property building item | Mar. 31, 2014 | Apr. 30, 2015 building property sqft | Dec. 31, 2014 community item | Jan. 31, 2015 property building sqft state | May 01, 2015 | May 31, 2015 community item | Dec. 31, 2014 community state item
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties owned |  | 392 us-gaap_NumberOfRealEstateProperties |  |  |  |  |  |  |
Number of buildings owned |  | 419 snh_NumberOfBuildings |  |  |  |  |  |  |
Number of states in which properties are located |  | 39 us-gaap_NumberOfStatesInWhichEntityOperates |  |  |  |  |  |  |
Real estate properties, at cost |  | $ 6,717,946 us-gaap_RealEstateInvestmentPropertyAtCost |  |  | 6,238,611 us-gaap_RealEstateInvestmentPropertyAtCost |  |  |  | 6,238,611 us-gaap_RealEstateInvestmentPropertyAtCost
Accumulated depreciation |  | 1,023,843 us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation |  |  | 983,850 us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation |  |  |  | 983,850 us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation
Assumption of mortgage notes payable |  | 29,955 us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 |  |  |  |  |  |  |
Number of properties classified as held for sale |  | 4 snh_NumberOfRealEstatePropertiesHeldForSale |  |  |  |  |  |  |
Number of buildings classified as held for sale |  | 7 snh_NumberOfBuildingsHeldForSale |  |  |  |  |  |  |
Number of properties to be sold | 1 snh_NumberOfPropertiesSold |  |  |  |  |  |  |  |
Gain on the sale of property |  |  | 156 us-gaap_GainLossOnSaleOfProperties |  |  |  |  |  |
Five Star |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Real estate improvements purchased |  | 4,550 snh_RealEstateImprovementsByLesseePurchased / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember | 8,614 snh_RealEstateImprovementsByLesseePurchased / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember |  |  |  |  |  |
Increase or decrease in annual lease rent payable |  | 367 snh_IncreaseDecreaseOperatingLeasesAnnualRent / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember | 689 snh_IncreaseDecreaseOperatingLeasesAnnualRent / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember |  |  |  |  |  |
MOBs |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties classified as held for sale |  | 1 snh_NumberOfRealEstatePropertiesHeldForSale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember | 4 snh_NumberOfRealEstatePropertiesHeldForSale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember |  |  |  |  |  |
Number of buildings classified as held for sale |  | 4 snh_NumberOfBuildingsHeldForSale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember | 7 snh_NumberOfBuildingsHeldForSale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember |  |  |  |  |  |
Property held for sale (in square feet) |  | 323,541 snh_AreaOfRealEstatePropertyHeldForSale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember |  |  |  |  |  |  |
Number of buildings sold |  |  |  | 4 snh_NumberOfBuildingsSold / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember |  |  |  |  |
Sale price of property sold and agreed to be sold |  |  |  | 1,500 snh_RealEstateAggregateSalesPrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember |  |  |  |  |
Senior living communities |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of communities |  |  |  |  | 5 snh_NumberOfCommunities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember |  |  |  |
Number of living units |  | 192 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember |  |  | 395 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember |  |  |  | 395 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember
Number of properties classified as held for sale |  | 3 snh_NumberOfRealEstatePropertiesHeldForSale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember |  |  |  |  |  |  |
Real estate properties, held for sale |  | 3,145 us-gaap_RealEstateHeldforsale / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember |  |  |  |  |  |  |
Senior living communities | Five Star |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties acquired, referred to as managed properties |  | 46 snh_NumberOfPropertiesAcquiredManagedProperties / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember |  |  |  |  |  |  |
Number of communities |  |  |  |  | 14 snh_NumberOfCommunities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember |  |  |  |
Number of living units |  |  |  |  | 881 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember |  |  |  | 881 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember
Fees paid to terminate the agreement |  |  |  |  | 975 us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember |  |  |  | 975 us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember
Independent living facility |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units |  |  |  |  | 826 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_IndependentLivingFacilityMember |  |  |  | 826 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_IndependentLivingFacilityMember
Assisted living facility |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units |  |  |  |  | 1,860 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_AssistedLivingFacilityMember |  |  |  | 1,860 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_AssistedLivingFacilityMember
Memory care facility |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units |  |  |  |  | 744 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MemoryCareFacilityMember |  |  |  | 744 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MemoryCareFacilityMember
Skilled nursing facilities |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units |  |  |  |  | 36 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SkilledNursingFacilityMember |  |  |  | 36 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SkilledNursingFacilityMember
Acquisition |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties acquired or agreed to be acquired |  | 23 snh_NumberOfPropertiesAcquired / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  |  |  |  |
Assumption of mortgage notes payable |  | 29,955 us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  |  |  |  |
Acquisition | MOBs |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties acquired or agreed to be acquired |  | 23 snh_NumberOfPropertiesAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  | 2 snh_NumberOfPropertiesAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember | 23 snh_NumberOfPropertiesAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Number of buildings acquired |  |  |  |  | 3 snh_NumberOfBuildingsAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember | 23 snh_NumberOfBuildingsAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Number of states in which property is located |  |  |  |  |  | 12 snh_NumberOfStatesInWhichProertyIsLocated / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Cash Paid plus Assumed Debt, excluding closing costs |  |  |  |  |  | 539,000 snh_RealEstateAggregatePurchasePrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Assumption of mortgage notes payable |  | (29,955)us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  | 15,630 us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember | (29,955)us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Weighted average interest rate on debt (as a percent) |  |  |  |  |  | 4.73%snh_DebtWeightedAverageInterestRateDuringThePeriod / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Area of real estate properties (in square feet) |  | 2,170,000 us-gaap_AreaOfRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | 2,170,000 us-gaap_AreaOfRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Cash Paid plus Assumed Debt, excluding closing costs plus other settlement adjustments |  | 539,000 snh_RealEstateAggregatePurchasePriceIncludingOtherSettlementAdjustments / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | 539,000 snh_RealEstateAggregatePurchasePriceIncludingOtherSettlementAdjustments / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Premium on Assumed Debt |  | (1,074)snh_NoncashOrPartNoncashAcquisitionPremiumOnDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | (1,074)snh_NoncashOrPartNoncashAcquisitionPremiumOnDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Intangible lease assets recorded |  | 85,496 snh_RealEstatePropertiesAcquiredIntangibleLeaseAssets / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | 85,496 snh_RealEstatePropertiesAcquiredIntangibleLeaseAssets / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Intangible lease liabilities recorded |  | (3,298)snh_RealEstatePropertiesAcquiredIntangibleLeaseLiabilities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | (3,298)snh_RealEstatePropertiesAcquiredIntangibleLeaseLiabilities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Acquisition | Senior living communities |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties acquired or agreed to be acquired |  |  |  |  | 2 snh_NumberOfPropertiesAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  |
Acquisition | Senior living communities | Subsequent event |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units |  |  |  |  |  |  | 3,379 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember |  |
Number of living units with delayed closing |  |  |  |  |  |  | 87 snh_NumberOfUnitsInRealEstatePropertyDelayedClosing / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember |  |
Cash Paid plus Assumed Debt, excluding closing costs |  |  |  |  |  |  | 762,611 snh_RealEstateAggregatePurchasePrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember |  |
Acquisition | Senior living communities | Five Star |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of communities |  |  |  |  |  |  |  | 14 snh_NumberOfCommunities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |
Number of living units |  |  |  |  |  |  |  | 881 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |
Agreement to acquire | Senior living communities |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of properties acquired or agreed to be acquired |  |  |  |  | 38 snh_NumberOfPropertiesAcquired / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  |
Number of communities |  |  |  |  |  |  |  | 37 snh_NumberOfCommunities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember | 38 snh_NumberOfCommunities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember
Number of living units |  |  |  |  | 3,466 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  | 3,466 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember
Number of states in which property is located |  |  |  |  | 16 snh_NumberOfStatesInWhichProertyIsLocated / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  | 16 snh_NumberOfStatesInWhichProertyIsLocated / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember
Cash Paid plus Assumed Debt, excluding closing costs |  |  |  |  | 790,000 snh_RealEstateAggregatePurchasePrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  |
Assumption of mortgage notes payable |  |  |  |  | 153,000 us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  | 139,181 us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1 / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |
Weighted average interest rate on debt (as a percent) |  |  |  |  | 4.77%snh_DebtWeightedAverageInterestRateDuringThePeriod / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  | 4.59%snh_DebtWeightedAverageInterestRateDuringThePeriod / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |
Agreement to acquire | Senior living communities | Leasing Member |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of communities |  |  |  |  | 19 snh_NumberOfCommunities / us-gaap_LeaseArrangementTypeAxis = snh_LeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  |
Number of living units |  |  |  |  | 2,190 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_LeaseArrangementTypeAxis = snh_LeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  | 2,190 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_LeaseArrangementTypeAxis = snh_LeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember
Number of communities not yet acquired |  |  |  |  | 1 snh_NumberOfCommunitiesNotYetAcquired / us-gaap_LeaseArrangementTypeAxis = snh_LeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  |
Number of operators |  |  |  |  | 7 snh_NumberOfOperators / us-gaap_LeaseArrangementTypeAxis = snh_LeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  |
Agreement to acquire | Senior living communities | TRS | Non Leasing Member |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of communities |  |  |  |  | 19 snh_NumberOfCommunities / us-gaap_LeaseArrangementTypeAxis = snh_NonLeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / snh_OperatingLeasesOfLessorLesseeAxis = snh_TaxableREITSubsidiariesMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  |
Number of living units |  |  |  |  | 1,276 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_LeaseArrangementTypeAxis = snh_NonLeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / snh_OperatingLeasesOfLessorLesseeAxis = snh_TaxableREITSubsidiariesMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember |  |  |  | 1,276 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_LeaseArrangementTypeAxis = snh_NonLeasingMember / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / snh_OperatingLeasesOfLessorLesseeAxis = snh_TaxableREITSubsidiariesMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember
Land | Acquisition | MOBs |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Property plant and equipment recorded |  | 58,294 snh_RealEstatePropertiesAcquiredPropertyPlantAndEquipment / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_LandMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | 58,294 snh_RealEstatePropertiesAcquiredPropertyPlantAndEquipment / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_LandMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
Buildings and improvements | Acquisition | MOBs |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Property plant and equipment recorded |  | 399,582 snh_RealEstatePropertiesAcquiredPropertyPlantAndEquipment / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_BuildingImprovementsMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |  | 399,582 snh_RealEstatePropertiesAcquiredPropertyPlantAndEquipment / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_MedicalOfficeBuildingMember / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_BuildingImprovementsMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember |  |  |
GA | Senior living communities | Five Star |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units |  |  |  | 40 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_StatementGeographicalAxis = stpr_GA |  |  |  |  |
Cash Paid plus Assumed Debt, excluding closing costs plus other settlement adjustments |  |  |  | 9,750 snh_RealEstateAggregatePurchasePriceIncludingOtherSettlementAdjustments / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_StatementGeographicalAxis = stpr_GA |  |  |  |  |
GA | Agreement to acquire | Senior living communities |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of communities |  |  |  | 1 snh_NumberOfCommunities / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember / us-gaap_StatementGeographicalAxis = stpr_GA |  |  |  |  |
Number of living units |  |  |  | 40 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember / us-gaap_StatementGeographicalAxis = stpr_GA |  |  |  |  |
Cash Paid plus Assumed Debt, excluding closing costs |  |  |  | 9,750 snh_RealEstateAggregatePurchasePrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_AgreementToAcquireMember / us-gaap_StatementGeographicalAxis = stpr_GA |  |  |  |  |
Pennsylvania | Senior living communities |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Sale price of property sold and agreed to be sold | 250 snh_RealEstateAggregateSalesPrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_StatementGeographicalAxis = country_PA |  |  |  |  |  |  |  |
Pennsylvania | Sale | Senior living communities | Five Star |  |  |  |  |  |  |  |  |
Real Estate Properties |  |  |  |  |  |  |  |  |
Number of living units | 120 us-gaap_NumberOfUnitsInRealEstateProperty / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_SaleOfAssetsMember / us-gaap_StatementGeographicalAxis = country_PA |  |  |  |  |  |  |  |
Sale price of property sold and agreed to be sold | 250 snh_RealEstateAggregateSalesPrice / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_SaleOfAssetsMember / us-gaap_StatementGeographicalAxis = country_PA |  |  |  |  |  |  |  |
Increase or decrease in annual lease rent payable | 23 snh_IncreaseDecreaseOperatingLeasesAnnualRent / us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis = snh_SeniorLivingCommunityMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = snh_FiveStarQualityCareIncMember / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = snh_SaleOfAssetsMember / us-gaap_StatementGeographicalAxis = country_PA |  |  |  |  |  |  |  |

X
- Definition Represents the area of a real estate property, held for sale. + References No definition available. + Details
Name: | snh_AreaOfRealEstatePropertyHeldForSale
Namespace Prefix: | snh_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average interest rate on debt during the period. + References No definition available. + Details
Name: | snh_DebtWeightedAverageInterestRateDuringThePeriod
Namespace Prefix: | snh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the increase or decrease on the annual rent the lessee is obligated to pay on an operating lease. + References No definition available. + Details
Name: | snh_IncreaseDecreaseOperatingLeasesAnnualRent
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of premium on assumed debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. + References No definition available. + Details
Name: | snh_NoncashOrPartNoncashAcquisitionPremiumOnDebtAssumed1
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the number of buildings owned as of the balance sheet date. + References No definition available. + Details
Name: | snh_NumberOfBuildings
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition This element represents the number of buildings acquired or agreed to be acquired by the entity during the period. + References No definition available. + Details
Name: | snh_NumberOfBuildingsAcquired
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of buildings owned by the entity, which are classified as held for sale as of the balance sheet date. + References No definition available. + Details
Name: | snh_NumberOfBuildingsHeldForSale
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition This element represents the number of buildings sold by the entity. + References No definition available. + Details
Name: | snh_NumberOfBuildingsSold
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of communities. + References No definition available. + Details
Name: | snh_NumberOfCommunities
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of communities not yet acquired under the purchase agreement to acquire. + References No definition available. + Details
Name: | snh_NumberOfCommunitiesNotYetAcquired
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of operators or property managers. + References No definition available. + Details
Name: | snh_NumberOfOperators
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the number of properties acquired or agreed to be acquired by the entity during the period. + References No definition available. + Details
Name: | snh_NumberOfPropertiesAcquired
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of properties acquired or agreed to be acquired by the entity during the period, which are referred by the entity as managed properties. + References No definition available. + Details
Name: | snh_NumberOfPropertiesAcquiredManagedProperties
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the number of properties sold or agreed to be sold by the entity. + References No definition available. + Details
Name: | snh_NumberOfPropertiesSold
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of real estate properties owned by the entity, which are classified as held for sale as of the balance sheet date. + References No definition available. + Details
Name: | snh_NumberOfRealEstatePropertiesHeldForSale
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of states in which the comapnies property is located. + References No definition available. + Details
Name: | snh_NumberOfStatesInWhichProertyIsLocated
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of units in a real estate property owned with an agreement for delayed closing as of the balance sheet date. + References No definition available. + Details
Name: | snh_NumberOfUnitsInRealEstatePropertyDelayedClosing
Namespace Prefix: | snh_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition This element represents the aggregate purchase price excluding closing costs, of real estate properties acquired by the entity during the period. + References No definition available. + Details
Name: | snh_RealEstateAggregatePurchasePrice
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This element represents the aggregate purchase price of real estate properties acquired by the entity during the period. This amount includes cash paid plus debt assumed, if any, and other settlement adjustments but excludes closing costs. + References No definition available. + Details
Name: | snh_RealEstateAggregatePurchasePriceIncludingOtherSettlementAdjustments
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This element represents the aggregate sales price excluding closing costs, of real estate properties sold by the entity during the period. + References No definition available. + Details
Name: | snh_RealEstateAggregateSalesPrice
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the amount of improvements to real estate properties made by lessees and purchased by the entity. + References No definition available. + Details
Name: | snh_RealEstateImprovementsByLesseePurchased
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the intangible lease assets recorded as part of the real estate acquisition. + References No definition available. + Details
Name: | snh_RealEstatePropertiesAcquiredIntangibleLeaseAssets
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the intangible lease liabilities recorded as part of the real estate acquisition. + References No definition available. + Details
Name: | snh_RealEstatePropertiesAcquiredIntangibleLeaseLiabilities
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the property plant and equipment assets recorded as part of the real estate acquisition. + References No definition available. + Details
Name: | snh_RealEstatePropertiesAcquiredPropertyPlantAndEquipment
Namespace Prefix: | snh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Area of a real estate property. + References No definition available. + Details
Name: | us-gaap_AreaOfRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_GainLossOnSaleOfProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of early contract termination fees included in liabilities subject to compromise. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 55 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=34712771&loc=d3e56145-112766 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6916575&loc=d3e55717-112764 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6918054&loc=d3e56015-112765 + Details
Name: | us-gaap_LiabilitiesSubjectToCompromiseEarlyContractTerminationFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 + Details
Name: | us-gaap_NoncashOrPartNoncashAcquisitionDebtAssumed1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The number of real estate properties owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfRealEstateProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of states the entity operates in as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of units in a real estate property owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(f)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_RealEstateHeldforsale
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cumulative amount of depreciation for real estate property held for investment purposes. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(3)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 7 + Details
Name: | us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_RealEstateInvestmentPropertyAtCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=snh_AssistedLivingFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=snh_IndependentLivingFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=snh_MedicalOfficeBuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=snh_MemoryCareFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=snh_SeniorLivingCommunityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=snh_SkilledNursingFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LandMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=snh_FiveStarQualityCareIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis=snh_AgreementToAcquireMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis=us-gaap_SeriesOfIndividuallyImmaterialBusinessAcquisitionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=country_PA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementGeographicalAxis=stpr_GA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |