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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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-Publisher FASB
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Amount of gain (loss) on sale or disposal of other assets.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-Topic 230
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The number of real estate properties owned as of the balance sheet date.

No definition available.

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Data Type:	xbrli:integerItemType
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The number of states the entity operates in as of the balance sheet date.

No definition available.

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Data Type:	xbrli:integerItemType
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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.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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Data Type:	na
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Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=dhc_SeniorLivingCommunitiesMember
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Data Type:	na
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Period Type:

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=dhc_SkilledNursingBedLicenseMember
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Data Type:	na
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Data Type:	na
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Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember
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Data Type:	na
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