Number of persons employed by the Entity

No definition available.

Name:	dei_EntityNumberOfEmployees
Namespace Prefix:	dei_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the business management fees incurred pursuant to business management agreement with related parties.

+ References

No definition available.

+ Details

Name:	dhc_BusinessManagementFees
Namespace Prefix:	dhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number Joint Venture Arrangements

+ References

No definition available.

+ Details

Name:	dhc_NumberJointVentureArrangements
Namespace Prefix:	dhc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Medical Office And Life Science Properties

+ References

No definition available.

+ Details

Name:	dhc_NumberOfMedicalOfficeAndLifeScienceProperties
Namespace Prefix:	dhc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Equity Method Investment Sold

+ References

No definition available.

+ Details

Name:	dhc_PercentageOfEquityMethodInvestmentSold
Namespace Prefix:	dhc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period Of Actual Amount Of Incentive Fees

+ References

No definition available.

+ Details

Name:	dhc_PeriodOfActualAmountOfIncentiveFees
Namespace Prefix:	dhc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the property management and construction supervision fees incurred pursuant to business and property management agreements with related parties.

+ References

No definition available.

+ Details

Name:	dhc_PropertyManagementAndConstructionSupervisionFees
Namespace Prefix:	dhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Property Management And Construction Supervision Fees, Capitalized

+ References

No definition available.

+ Details

Name:	dhc_PropertyManagementAndConstructionSupervisionFeesCapitalized
Namespace Prefix:	dhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the property management and construction supervision fees paid to related parties.

+ References

No definition available.

+ Details

Name:	dhc_PropertyManagementAndConstructionSupervisionFeesPaid
Namespace Prefix:	dhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the number of consecutive renewal terms of agreement that the entity has the option to renew.

+ References

No definition available.

+ Details

Name:	dhc_RelatedPartyTransactionPropertyManagementAgreementNumberOfConsecutiveRenewalTerms
Namespace Prefix:	dhc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=dhc_ReitManagementAndResearchMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_CorporateJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=dhc_SeaportInnovationLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=dhc_SeniorLivingCommunityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Business and Property Management Agreements with RMR (Details) $ in Thousands	1 Months Ended		3 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Mar. 31, 2023 USD ($) employee agreement property jointVenture_arrangement	Mar. 31, 2022 USD ($)	Jun. 28, 2022	Dec. 30, 2021
Related person transactions
Number of employees \| employee			0
Property management and construction supervision fees			$ 1,992	$ 2,391
Property management and construction supervision fees paid			3,533	2,964
RMR
Related person transactions
Business management fees incurred			$ 3,270	4,813
Period of actual amount of incentive fees			3 years
Property management and construction supervision fees			$ 1,463	1,349
Party transaction property management and construction supervision fees capitalized			$ 529	$ 1,042
Number joint venture arrangements \| jointVenture_arrangement			2
Number of medical office and life science properties \| property			10
Corporate Joint Venture \| Seaport Innovation LLC
Related person transactions
Additional equity joint venture percentage	10.00%	35.00%
Equity method investment ownership percentage			10.00%		20.00%	55.00%
Senior Living Communities \| RMR
Related person transactions
Number of consecutive renewal terms of agreement \| agreement			2