Interim Condensed Consolidated Statements of Operations (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Other revenues	$ 11,269,000	$ 11,284,000
Net operating revenues	242,961,000	238,538,000
Costs and expenses:
Salaries, wages and benefits	140,095,000	138,055,000
Other operating	65,172,000	63,178,000
Facility rent	10,229,000	10,088,000
Depreciation and amortization	10,342,000	10,295,000
Interest	1,240,000	1,058,000
Total costs and expenses	227,078,000	222,674,000
Income from operations	15,883,000	15,864,000
Non–operating income (expense)	(3,065,000)	4,768,000
Unrealized losses on marketable equity securities	(15,517,000)
Income (loss) before income taxes	(2,699,000)	20,632,000
Income tax provision	(200,000)	(7,999,000)
Net income (loss)	(2,899,000)	12,633,000
Net loss attributable to noncontrolling interest	108,000	95,000
Net income (loss) attributable to National HealthCare Corporation	$ (2,791,000)	$ 12,728,000
Earnings (loss) per share attributable to National HealthCare Corporation stockholders:
Basic (in dollars per share)	$ (0.18)	$ 0.84
Diluted (in dollars per share)	$ (0.18)	$ 0.84
Weighted average common shares outstanding:
Basic (in shares)	15,216,635	15,173,491
Diluted (in shares)	15,216,635	15,212,133
Dividends declared to common stockholders, per share (in dollars per share)	$ 0.48	$ 0.45
Net Patient Revenues [Member]
Revenues:
Revenues	$ 231,692,000	$ 227,254,000