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The percentage of the resident entry fee that becomes nonrefundable upon occupancy.

No definition available.

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Remaining refundable portion of the resident's entry fee.

No definition available.

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Amount of allowance for credit loss on accounts receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount of refund obligation under existing contract for continuing care retirement community.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 440
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Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
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-Section 55
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-URI http://asc.fasb.org/extlink&oid=121551570&loc=SL49130611-203046-203046

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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Data Type:	xbrli:durationItemType
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Period Type:	instant

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
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Data Type:	xbrli:integerItemType
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Period Type:	duration

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.

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

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

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

Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=nhc_RefundableAdvanceFeesMember
Namespace Prefix:
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Balance Type:
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Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=nhc_OriginalEntryFeeMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_HealthCareOrganizationRevenueSourcesAxis=nhc_AppreciationMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=nhc_EquipmentAndFurnitureMember
Namespace Prefix:
Data Type:	na
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