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Note 12 - Stock-based Compensation (Details) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
May 31, 2005
May 31, 2010
Note 12 - Stock-based Compensation (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period 11,623us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod      
Allocated Share-based Compensation Expense $ 478,000us-gaap_AllocatedShareBasedCompensationExpense $ 482,000us-gaap_AllocatedShareBasedCompensationExpense    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized 1,571,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized      
Incentive Stock Option [Member] | Minimum [Member]        
Note 12 - Stock-based Compensation (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years      
Employee Stock Option [Member]        
Note 12 - Stock-based Compensation (Details) [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized 1,550,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
     
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 328 days      
Restricted Stock [Member]        
Note 12 - Stock-based Compensation (Details) [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized $ 21,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
     
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 36 days      
2005 Plan [Member]        
Note 12 - Stock-based Compensation (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized     1,200,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= nhc_TwoThousandFivePlanMember
 
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 220,620us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= nhc_TwoThousandFivePlanMember
     
2010 Plan [Member]        
Note 12 - Stock-based Compensation (Details) [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized       1,200,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
/ us-gaap_PlanNameAxis
= nhc_TwoThousandTenPlanMember
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 387,121us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
/ us-gaap_PlanNameAxis
= nhc_TwoThousandTenPlanMember