Note 18 - Series A Convertible Preferred Stock	12 Months Ended
Dec. 31, 2014
Disclosure Text Block Supplement [Abstract]
Preferred Stock [Text Block]	Note 18 - Series A Convertible Preferred Stock On October 31, 2007, NHC issued $170,555,000 of NHC Series A Convertible Preferred Stock (the "Preferred Stock") with a liquidation preference of $15.75. Each share of the Preferred Stock is entitled to annual preferred dividends of $0.80 per share. Dividends on the Preferred Stock are cumulative. The Preferred Stock, which is listed on the NYSE MKT exchange with the symbol "NHC.PRA", is convertible at any time at the option of the stockholder into NHC common stock at a conversion price of $65.07. Each share of the Preferred Stock will be convertible into 0.24204 of a share of NHC common stock. After the fifth anniversary of the closing date, NHC will have the option to redeem the Preferred Stock, in whole or in part, for $15.75 cash per share (plus accrued but unpaid dividends); provided that the Preferred Stock will not be redeemable prior to the eighth anniversary of the closing date unless the average closing price for NHC common stock for 20 trading sessions equals or exceeds the conversion price. The conversion price will be adjusted to reflect any future NHC common stock splits or stock dividends.

Note 18 - Series A Convertible Preferred Stock

12 Months Ended

Dec. 31, 2014

Disclosure Text Block Supplement [Abstract]

Note 18 - Series A Convertible Preferred Stock

On October 31, 2007, NHC issued $170,555,000 of NHC Series A Convertible Preferred Stock (the "Preferred Stock") with a liquidation preference of $15.75. Each share of the Preferred Stock is entitled to annual preferred dividends of $0.80 per share. Dividends on the Preferred Stock are cumulative.

The Preferred Stock, which is listed on the NYSE MKT exchange with the symbol "NHC.PRA", is convertible at any time at the option of the stockholder into NHC common stock at a conversion price of $65.07. Each share of the Preferred Stock will be convertible into 0.24204 of a share of NHC common stock. After the fifth anniversary of the closing date, NHC will have the option to redeem the Preferred Stock, in whole or in part, for $15.75 cash per share (plus accrued but unpaid dividends); provided that the Preferred Stock will not be redeemable prior to the eighth anniversary of the closing date unless the average closing price for NHC common stock for 20 trading sessions equals or exceeds the conversion price. The conversion price will be adjusted to reflect any future NHC common stock splits or stock dividends.