Cash Paid plus Assumed Debt, including closing costs plus other settlement adjustments

No definition available.

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Balance Type:	debit
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- 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the intangible lease assets recorded as part of the real estate acquisition.

+ References

No definition available.

+ Details

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Namespace Prefix:	dhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the intangible lease liabilities recorded as part of the real estate acquisition.

+ References

No definition available.

+ Details

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Namespace Prefix:	dhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4313-108586

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of real estate investment property, net of accumulated depreciation, 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://fasb.org/us-gaap/role/ref/legacyRef
-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=120400017&loc=d3e572229-122910

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

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Period Type:	duration

- Details

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- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=dhc_MedicalOfficeBuildingandLifeScienceBuildingMember
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- Details

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- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=dhc_AssistedLivingMember
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Balance Type:
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- Details

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- Details

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- Details

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- Details

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Data Type:	na
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- Details

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Real Estate Properties - Schedule of Acquisitions (Details) $ in Thousands	1 Months Ended					12 Months Ended
	Dec. 31, 2019 USD ($) property unit	Jun. 30, 2018 USD ($) property unit	Mar. 31, 2018 USD ($) ft² property	Feb. 28, 2018 USD ($) unit property	Jan. 31, 2018 USD ($) ft² property unit	Dec. 31, 2020 USD ($) ft² property	Dec. 31, 2019 USD ($) property unit	Dec. 31, 2018 USD ($) property
Real Estate
Number of Properties \| property						397
Net Book Value of Collateral	$ 5,890,785					$ 5,715,829	$ 5,890,785
Assumed Debt						$ 0	$ 0	$ (44,386)
Acquisitions
Real Estate
Number of Properties \| property								8
Cash Paid plus Assumed Debt								$ 181,323
Acquired Real Estate Leases / Resident Agreements								41,016
Acquired Real Estate Lease Obligations								0
Assumed Debt								(44,386)
Premium on Assumed Debt								(1,845)
Medical Office / Life Science
Real Estate
Number of Properties \| property						123
Area of real estate properties (in square feet) \| ft²						11,300,000
Medical Office / Life Science \| 3 States \| Acquisitions
Real Estate
Number of Properties \| property					3
Area of real estate properties (in square feet) \| ft²					400,000
Cash Paid plus Assumed Debt					$ 91,698
Acquired Real Estate Leases / Resident Agreements					20,220
Acquired Real Estate Lease Obligations					0
Assumed Debt					0
Premium on Assumed Debt					$ 0
AL \| Tennessee \| Acquisitions
Real Estate
Number of Properties \| property					1
Number of Units \| unit					88
Cash Paid plus Assumed Debt					$ 19,868
Acquired Real Estate Leases / Resident Agreements					3,195
Acquired Real Estate Lease Obligations					0
Assumed Debt					0
Premium on Assumed Debt					0
IL \| Texas \| Acquisitions
Real Estate
Number of Properties \| property	1						1
Number of Units \| unit	169						169
Cash Paid plus Assumed Debt	$ 50,506
Acquired Real Estate Leases / Resident Agreements	2,202						$ 2,202
Acquired Real Estate Lease Obligations	0						$ 0
Assumed Debt	0
Premium on Assumed Debt	$ 0
IL \| Tennessee \| Acquisitions
Real Estate
Number of Properties \| property		2
Number of Units \| unit		151
Cash Paid plus Assumed Debt		$ 23,860
Acquired Real Estate Leases / Resident Agreements		3,843
Acquired Real Estate Lease Obligations		0
Assumed Debt		(16,588)
Premium on Assumed Debt		(486)
IL \| Arizona \| Acquisitions
Real Estate
Number of Properties \| property				1
Number of Units \| unit				127
Cash Paid plus Assumed Debt				$ 22,622
Acquired Real Estate Leases / Resident Agreements				4,451
Acquired Real Estate Lease Obligations				0
Assumed Debt				(16,748)
Premium on Assumed Debt				(1,359)
Medical Office
Real Estate
Number of Properties \| property	20					7	20
Medical Office \| Virginia \| Acquisitions
Real Estate
Number of Properties \| property			1
Area of real estate properties (in square feet) \| ft²			135,000
Cash Paid plus Assumed Debt			$ 23,275
Acquired Real Estate Leases / Resident Agreements			9,307
Acquired Real Estate Lease Obligations			0
Assumed Debt			(11,050)
Premium on Assumed Debt			0
Land
Real Estate
Net Book Value of Collateral	$ 793,123					$ 789,125	$ 793,123
Land \| Acquisitions
Real Estate
Net Book Value of Collateral								23,298
Land \| Medical Office / Life Science \| 3 States \| Acquisitions
Real Estate
Net Book Value of Collateral					16,873
Land \| AL \| Tennessee \| Acquisitions
Real Estate
Net Book Value of Collateral					580
Land \| IL \| Texas \| Acquisitions
Real Estate
Net Book Value of Collateral	3,463						3,463
Land \| IL \| Tennessee \| Acquisitions
Real Estate
Net Book Value of Collateral		965
Land \| IL \| Arizona \| Acquisitions
Real Estate
Net Book Value of Collateral				2,017
Land \| Medical Office \| Virginia \| Acquisitions
Real Estate
Net Book Value of Collateral			2,863
Buildings and Improvements
Real Estate
Net Book Value of Collateral	6,668,463					$ 6,621,605	6,668,463
Buildings and Improvements \| Acquisitions
Real Estate
Net Book Value of Collateral								115,627
Buildings and Improvements \| Medical Office / Life Science \| 3 States \| Acquisitions
Real Estate
Net Book Value of Collateral					54,605
Buildings and Improvements \| AL \| Tennessee \| Acquisitions
Real Estate
Net Book Value of Collateral					14,884
Buildings and Improvements \| IL \| Texas \| Acquisitions
Real Estate
Net Book Value of Collateral	44,189						44,189
Buildings and Improvements \| IL \| Tennessee \| Acquisitions
Real Estate
Net Book Value of Collateral		17,910
Buildings and Improvements \| IL \| Arizona \| Acquisitions
Real Estate
Net Book Value of Collateral				17,123
Buildings and Improvements \| Medical Office \| Virginia \| Acquisitions
Real Estate
Net Book Value of Collateral			11,105
FF&E \| Acquisitions
Real Estate
Net Book Value of Collateral								$ 3,227
FF&E \| Medical Office / Life Science \| 3 States \| Acquisitions
Real Estate
Net Book Value of Collateral					0
FF&E \| AL \| Tennessee \| Acquisitions
Real Estate
Net Book Value of Collateral					$ 1,209
FF&E \| IL \| Texas \| Acquisitions
Real Estate
Net Book Value of Collateral	$ 652						$ 652
FF&E \| IL \| Tennessee \| Acquisitions
Real Estate
Net Book Value of Collateral		$ 1,628
FF&E \| IL \| Arizona \| Acquisitions
Real Estate
Net Book Value of Collateral				$ 390
FF&E \| Medical Office \| Virginia \| Acquisitions
Real Estate
Net Book Value of Collateral			$ 0