Note 1 - Description of Business (Details)	Jun. 30, 2015
Disclosure Text Block [Abstract]
Number of Skilled Nursing Centers	75
Number Of Beds	9,423
Number Of Assisted Living Facilities	19
Number Of Independent Living Facilities	5
Number Of Homecare Programs	36
Number of States in which Entity Operates	10

Number of assisted living facilities in which company operates as of the Balance Sheet date.

No definition available.

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Number of licensed skilled nursing beds that are operated or managed as of the balance sheet date.

No definition available.

Number of homecare Programs in which the company operates as of the Balance Sheet date.

No definition available.

Name:	nhc_NumberOfHomecarePrograms
Namespace Prefix:	nhc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of independent living facilities in which the company operates as of the Balance Sheet date.

No definition available.

Name:	nhc_NumberOfIndependentLivingFacilities
Namespace Prefix:	nhc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of skilled nursing centers operated or managed as of the balance sheet date.

No definition available.

Name:	nhc_NumberOfSkilledNursingCenters
Namespace Prefix:	nhc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

No definition available.

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The number of states the entity operates in as of the balance sheet date.

No definition available.

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