$NHC
NATIONAL HEALTHCARE CORP Stock $nhc

$nhc Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-K Financial Statement

#000143774921003415 Filed on February 19, 2021

Income Statement

Concept	2020 Q4	2019 Q4	2018 Q4
Revenue	$259.8M	$253.9M	$248.9M
YoY Change	2.34%	1.99%	1.06%
Cost Of Revenue	$147.4M	$151.4M	$148.0M
YoY Change	-2.67%	2.31%	1.77%
Gross Profit	$112.5M	$102.5M	$100.9M
YoY Change	9.74%	1.53%	0.85%
Gross Profit Margin	43.29%	40.37%	40.55%
Selling, General & Admin	$9.522M	$9.916M	$10.23M
YoY Change	-3.97%	-3.09%	1.31%
% of Gross Profit	8.47%	9.68%	10.14%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$10.49M	$10.90M	$10.69M
YoY Change	-3.82%	1.96%	-3.66%
% of Gross Profit	9.32%	10.64%	10.59%
Operating Expenses	$76.04M	$85.50M	$82.72M
YoY Change	-11.07%	3.36%	0.39%
Operating Profit	$36.43M	$16.50M	$17.19M
YoY Change	120.85%	-4.05%	5.34%
Interest Expense	$24.02M	$1.454M	$6.301M
YoY Change	1552.06%	-76.92%	103.26%
% of Operating Profit	65.93%	8.81%	36.65%
Other Income/Expense, Net		$5.811M	$6.614M
YoY Change		-12.14%	50.59%
Pretax Income	$37.05M	$18.44M	$24.53M
YoY Change	100.89%	-24.82%	18.5%
Income Tax	$9.633M	$4.755M	$4.959M
% Of Pretax Income	26.0%	25.78%	20.22%
Net Earnings	$27.55M	$13.77M	$18.15M
YoY Change	100.07%	-24.14%	-15.57%
Net Earnings / Revenue	10.6%	5.42%	7.29%
Basic Earnings Per Share		$0.91	$1.19
Diluted Earnings Per Share	$1.792M	$0.89	$1.19
COMMON SHARES
Basic Shares Outstanding	15.36M
Diluted Shares Outstanding

Balance Sheet

Concept	2020 Q4	2019 Q4	2018 Q4
SHORT-TERM ASSETS
Cash & Short-Term Investments	$470.2M	$70.91M	$61.92M
YoY Change	563.09%	14.51%	-22.72%
Cash & Equivalents	$147.1M	$50.33M	$43.25M
Short-Term Investments	$323.1M	$20.58M	$18.68M
Other Short-Term Assets	$33.93M	$33.60M	$32.51M
YoY Change	1.0%	3.35%	7.28%
Inventory	$8.781M	$7.441M	$7.470M
Prepaid Expenses
Receivables	$89.67M	$92.98M	$97.27M
Other Receivables	$928.0K	$4.255M	$1.289M
Total Short-Term Assets	$456.8M	$341.1M	$322.0M
YoY Change	33.92%	5.91%	-2.22%
LONG-TERM ASSETS
Property, Plant & Equipment	$520.3M	$535.4M	$534.7M
YoY Change	-2.82%	0.15%	-2.67%
Goodwill	$168.3M	$21.00M	$21.00M
YoY Change	701.6%	0.0%	19.29%
Intangibles	$0.00
YoY Change
Long-Term Investments	$40.78M	$39.19M	$32.36M
YoY Change	4.06%	21.1%	-10.85%
Other Assets	$385.1M	$410.2M	$224.3M
YoY Change	-6.12%	82.87%	2.93%
Total Long-Term Assets	$905.4M	$945.6M	$758.9M
YoY Change	-4.25%	24.59%	-1.08%
TOTAL ASSETS
Total Short-Term Assets	$456.8M	$341.1M	$322.0M
Total Long-Term Assets	$905.4M	$945.6M	$758.9M
Total Assets	$1.362B	$1.287B	$1.081B
YoY Change	5.87%	19.03%	-1.42%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$21.11M	$18.90M	$19.76M
YoY Change	11.69%	-4.33%	23.49%
Accrued Expenses	$142.6M	$123.6M	$96.26M
YoY Change	15.37%	28.39%	1.86%
Deferred Revenue	$51.25M	$0.00
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$0.00	$10.00M	$0.00
YoY Change	-100.0%
Total Short-Term Liabilities	$281.2M	$194.8M	$157.9M
YoY Change	44.39%	23.33%	1.84%
LONG-TERM LIABILITIES
Long-Term Debt	$10.54M	$0.00	$55.00M
YoY Change		-100.0%	-45.0%
Other Long-Term Liabilities	$28.38M	$21.23M	$15.20M
YoY Change	33.66%	39.63%	-3.74%
Total Long-Term Liabilities	$28.38M	$21.23M	$70.20M
YoY Change	33.66%	-69.76%	-39.37%
TOTAL LIABILITIES
Total Short-Term Liabilities	$281.2M	$194.8M	$157.9M
Total Long-Term Liabilities	$28.38M	$21.23M	$70.20M
Total Liabilities	$563.9M	$507.6M	$346.5M
YoY Change	11.09%	46.49%	-11.86%
SHAREHOLDERS EQUITY
Retained Earnings	$563.0M	$553.1M	$516.4M
YoY Change	1.8%	7.1%	23.13%
Common Stock	$153.0K	$153.0K	$153.0K
YoY Change	0.0%	0.0%	0.66%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$795.2M	$778.6M	$733.3M
YoY Change
Total Liabilities & Shareholders Equity	$1.362B	$1.287B	$1.081B
YoY Change	5.87%	19.03%	-1.42%

Cashflow Statement

Concept	2020 Q4	2019 Q4	2018 Q4
OPERATING ACTIVITIES
Net Income	$27.55M	$13.77M	$18.15M
YoY Change	100.07%	-24.14%	-15.57%
Depreciation, Depletion And Amortization	$10.49M	$10.90M	$10.69M
YoY Change	-3.82%	1.96%	-3.66%
Cash From Operating Activities	$19.36M	$25.22M	$21.34M
YoY Change	-23.24%	18.2%	-9.21%
INVESTING ACTIVITIES
Capital Expenditures	-$4.156M	-$6.730M	-$7.072M
YoY Change	-38.25%	-4.84%	-11.6%
Acquisitions
YoY Change
Other Investing Activities	-$44.45M	$2.288M	$510.0K
YoY Change	-2042.7%	348.63%	-118.89%
Cash From Investing Activities	-$48.61M	-$4.442M	-$6.562M
YoY Change	994.21%	-32.31%	-39.24%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-8.370M	-27.85M	-27.57M
YoY Change	-69.95%	1.0%	1.75%
NET CHANGE
Cash From Operating Activities	19.36M	25.22M	21.34M
Cash From Investing Activities	-48.61M	-4.442M	-6.562M
Cash From Financing Activities	-8.370M	-27.85M	-27.57M
Net Change In Cash	-37.62M	-7.072M	-12.80M
YoY Change	431.9%	-44.75%	-11.1%
FREE CASH FLOW
Cash From Operating Activities	$19.36M	$25.22M	$21.34M
Capital Expenditures	-$4.156M	-$6.730M	-$7.072M
Free Cash Flow	$23.51M	$31.95M	$28.41M
YoY Change	-26.4%	12.47%	-9.82%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2018	us-gaap	Revenues Revenues	980349000	USD
CY2018	nhc	Other Revenues OtherRevenues	47575000	USD
CY2020	nhc	Government Assistance Stimulus Income Cares Act GovernmentAssistanceStimulusIncomeCaresAct	47505000	USD
CY2019	nhc	Government Assistance Stimulus Income Cares Act GovernmentAssistanceStimulusIncomeCaresAct	0	USD
CY2018	nhc	Government Assistance Stimulus Income Cares Act GovernmentAssistanceStimulusIncomeCaresAct	0	USD
CY2020	us-gaap	Revenues Revenues	1028217000	USD
CY2019	us-gaap	Revenues Revenues	996383000	USD
CY2018	us-gaap	Depreciation And Amortization DepreciationAndAmortization	41894000	USD
CY2020	us-gaap	Interest Expense InterestExpense	1399000	USD
CY2019	us-gaap	Interest Expense InterestExpense	3135000	USD
CY2018	us-gaap	Interest Expense InterestExpense	4697000	USD
CY2020	us-gaap	Costs And Expenses CostsAndExpenses	980062000	USD
CY2019	us-gaap	Costs And Expenses CostsAndExpenses	947345000	USD
CY2021Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	15370042
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	45000000
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	45000000
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	15369745
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	15369745
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	15332206
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	15332206
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.98
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.06
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.08
CY2020	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	pure
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	12342000	USD
CY2020	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	2	pure
CY2019	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale	0	USD
CY2018	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale	0	USD
CY2020	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale	0	USD
CY2020	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	0	USD
CY2018	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	0	USD
CY2019	us-gaap	Proceeds From Sale And Maturity Of Marketable Securities ProceedsFromSaleAndMaturityOfMarketableSecurities	0	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	-0	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	10000000	USD
CY2019	nhc	Effective Income Tax Rate Reconciliation Benefit Resulting From Expiration Of Applicable Statute Limitations Amount EffectiveIncomeTaxRateReconciliationBenefitResultingFromExpirationOfApplicableStatuteLimitationsAmount	2064000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y
CY2020Q4	nhc	Number Of Variable Interest Entities NumberOfVariableInterestEntities	1	pure
CY2010Q4	nhc	Number Of Patient Beds In Facility NumberOfPatientBedsInFacility	120	pure
CY2010Q4	us-gaap	Lessee Operating Lease Term Of Contract LesseeOperatingLeaseTermOfContract	P10Y
CY2010Q4	nhc	Number Of Additional Lease Options NumberOfAdditionalLeaseOptions	5	pure
CY2010Q4	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P5Y
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	931795000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	947872000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	932774000	USD
CY2020	nhc	Other Revenues OtherRevenues	48917000	USD
CY2019	nhc	Other Revenues OtherRevenues	48511000	USD
CY2020	us-gaap	Labor And Related Expense LaborAndRelatedExpense	609306000	USD
CY2019	us-gaap	Labor And Related Expense LaborAndRelatedExpense	592831000	USD
CY2018	us-gaap	Labor And Related Expense LaborAndRelatedExpense	582721000	USD
CY2020	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	286845000	USD
CY2019	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	268442000	USD
CY2018	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	254038000	USD
CY2020	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	40494000	USD
CY2019	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	40518000	USD
CY2018	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	40923000	USD
CY2020	us-gaap	Depreciation And Amortization DepreciationAndAmortization	42018000	USD
CY2019	us-gaap	Depreciation And Amortization DepreciationAndAmortization	42419000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	26747000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	17670000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-23966000	USD
CY2018	us-gaap	Costs And Expenses CostsAndExpenses	924273000	USD
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	48155000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	49038000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	56076000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	28234000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	12230000	USD
CY2018	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1138000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	52423000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	88015000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	74884000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10433000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	20039000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16185000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	41990000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	67976000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	58699000	USD
CY2020	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	119000	USD
CY2019	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-235000	USD
CY2018	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-265000	USD
CY2020	us-gaap	Net Income Loss NetIncomeLoss	41871000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	68211000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	58964000	USD
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.74
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.47
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.87
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.72
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.44
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.87
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15306174
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15270154
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15224886
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	15369523
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	15360046
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	15236826
CY2020	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.08
CY2019	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	2.06
CY2018	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.98
CY2020	us-gaap	Profit Loss ProfitLoss	41990000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	67976000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	58699000	USD
CY2020	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	3352000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	6842000	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-2574000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	195000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	127000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	18000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	660000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	1410000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-544000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	2497000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	5305000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-2048000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	119000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-235000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	-265000	USD
CY2020	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	44368000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	73516000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	56916000	USD
CY2020Q4	us-gaap	Deposits Assets Noncurrent DepositsAssetsNoncurrent	4580000	USD
CY2019Q4	us-gaap	Deposits Assets Noncurrent DepositsAssetsNoncurrent	5124000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	179055000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	202909000	USD
CY2020Q4	us-gaap	Goodwill Goodwill	21341000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	20995000	USD
CY2020Q4	us-gaap	Notes And Loans Receivable Net Noncurrent NotesAndLoansReceivableNetNoncurrent	12093000	USD
CY2019Q4	us-gaap	Notes And Loans Receivable Net Noncurrent NotesAndLoansReceivableNetNoncurrent	13384000	USD
CY2020Q4	us-gaap	Investments In Affiliates Subsidiaries Associates And Joint Ventures InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures	40782000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	147093000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	50334000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	9673000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	8944000	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	128590000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	152453000	USD
CY2020Q4	us-gaap	Debt Securities Current DebtSecuritiesCurrent	47762000	USD
CY2019Q4	us-gaap	Debt Securities Current DebtSecuritiesCurrent	0	USD
CY2020Q4	us-gaap	Equity Securities Fv Ni Restricted EquitySecuritiesFvNiRestricted	4680000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni Restricted EquitySecuritiesFvNiRestricted	0	USD
CY2020Q4	nhc	Restricted Marketable Debt Securities Current RestrictedMarketableDebtSecuritiesCurrent	16601000	USD
CY2019Q4	nhc	Restricted Marketable Debt Securities Current RestrictedMarketableDebtSecuritiesCurrent	20576000	USD
CY2020Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	89670000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	92975000	USD
CY2020Q4	us-gaap	Inventory Net InventoryNet	8781000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	7441000	USD
CY2020Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	2977000	USD
CY2019Q4	us-gaap	Prepaid Expense And Other Assets Current PrepaidExpenseAndOtherAssetsCurrent	6635000	USD
CY2020Q4	us-gaap	Notes And Loans Receivable Net Current NotesAndLoansReceivableNetCurrent	928000	USD
CY2019Q4	us-gaap	Notes And Loans Receivable Net Current NotesAndLoansReceivableNetCurrent	1695000	USD
CY2020Q4	us-gaap	Assets Current AssetsCurrent	456755000	USD
CY2019Q4	us-gaap	Assets Current AssetsCurrent	341053000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1030426000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1017204000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	510108000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	481774000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	520318000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	535430000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	1736000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents Noncurrent RestrictedCashAndCashEquivalentsNoncurrent	1732000	USD
CY2020Q4	nhc	Restricted Marketable Debt Securities Noncurrent RestrictedMarketableDebtSecuritiesNoncurrent	125472000	USD
CY2019Q4	nhc	Restricted Marketable Debt Securities Noncurrent RestrictedMarketableDebtSecuritiesNoncurrent	126830000	USD
CY2019Q4	us-gaap	Investments In Affiliates Subsidiaries Associates And Joint Ventures InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures	39191000	USD
CY2020Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	385059000	USD
CY2019Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	410165000	USD
CY2020Q4	us-gaap	Assets Assets	1362132000	USD
CY2019Q4	us-gaap	Assets Assets	1286648000	USD
CY2020Q4	us-gaap	Accounts Payable Trade Current AccountsPayableTradeCurrent	21112000	USD
CY2019Q4	us-gaap	Accounts Payable Trade Current AccountsPayableTradeCurrent	18903000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	4423000	USD
CY2019Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	4166000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	25451000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	24243000	USD
CY2020Q4	us-gaap	Accrued Salaries Current AccruedSalariesCurrent	86183000	USD
CY2020	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	12342000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	9744000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1020000	USD
CY2020	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	10050000	USD
CY2019Q4	us-gaap	Accrued Salaries Current AccruedSalariesCurrent	69826000	USD
CY2020Q4	us-gaap	Accounts Payable Other Current AccountsPayableOtherCurrent	16454000	USD
CY2019Q4	us-gaap	Accounts Payable Other Current AccountsPayableOtherCurrent	15108000	USD
CY2020Q4	us-gaap	Self Insurance Reserve Current SelfInsuranceReserveCurrent	30953000	USD
CY2019Q4	us-gaap	Self Insurance Reserve Current SelfInsuranceReserveCurrent	29520000	USD
CY2020Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	21344000	USD
CY2019Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	15029000	USD
CY2020Q4	nhc	Provider Relief Funds ProviderReliefFunds	16068000	USD
CY2019Q4	nhc	Provider Relief Funds ProviderReliefFunds	0	USD
CY2020Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	51253000	USD
CY2019Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	0	USD
CY2020Q4	us-gaap	Dividends Payable Current DividendsPayableCurrent	7987000	USD
CY2019Q4	us-gaap	Dividends Payable Current DividendsPayableCurrent	7968000	USD
CY2020Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	10000000	USD
CY2020Q4	us-gaap	Liabilities Current LiabilitiesCurrent	281228000	USD
CY2019Q4	us-gaap	Liabilities Current LiabilitiesCurrent	194763000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	10540000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	14963000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	153604000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	178666000	USD
CY2020Q4	us-gaap	Self Insurance Reserve Noncurrent SelfInsuranceReserveNoncurrent	68584000	USD
CY2019Q4	us-gaap	Self Insurance Reserve Noncurrent SelfInsuranceReserveNoncurrent	66491000	USD
CY2020Q4	us-gaap	Contract With Customer Refund Liability Noncurrent ContractWithCustomerRefundLiabilityNoncurrent	7462000	USD
CY2019Q4	us-gaap	Contract With Customer Refund Liability Noncurrent ContractWithCustomerRefundLiabilityNoncurrent	7455000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	14079000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities Net DeferredIncomeTaxLiabilitiesNet	24012000	USD
CY2020Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	28375000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	21229000	USD
CY2020Q4	us-gaap	Liabilities Liabilities	563872000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	507579000	USD
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	153000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	153000	USD
CY2020Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	226943000	USD
CY2019Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	222787000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	563024000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	553093000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	5057000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	2560000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	795177000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	778593000	USD
CY2020Q4	us-gaap	Minority Interest MinorityInterest	3083000	USD
CY2019Q4	us-gaap	Minority Interest MinorityInterest	476000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	798260000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	779069000	USD
CY2020Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1362132000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1286648000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	41990000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	67976000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	58699000	USD
CY2020	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	42018000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	42419000	USD
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	41894000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	287000	USD
CY2018	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	1743000	USD
CY2020	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	1429000	USD
CY2018	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-718000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	-856000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable Trade IncreaseDecreaseInAccountsPayableTrade	3467000	USD
CY2020	us-gaap	Increase Decrease In Accrued Salaries IncreaseDecreaseInAccruedSalaries	15948000	USD
CY2019	us-gaap	Increase Decrease In Accrued Salaries IncreaseDecreaseInAccruedSalaries	2208000	USD
CY2018	us-gaap	Increase Decrease In Accrued Salaries IncreaseDecreaseInAccruedSalaries	516000	USD
CY2020	nhc	Increase Decrease In Due To Third Party Payors IncreaseDecreaseInDueToThirdPartyPayors	1200000	USD
CY2020	us-gaap	Share Based Compensation ShareBasedCompensation	2453000	USD
CY2020	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-41889000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	1878000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	1778000	USD
CY2020	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-4529000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-4299000	USD
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	9398000	USD
CY2020	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-0	USD
CY2019	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	2560000	USD
CY2018	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-5465000	USD
CY2020	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	1249000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-29000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	317000	USD
CY2020	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-4727000	USD
CY2019	us-gaap	Increase Decrease In Other Noncurrent Liabilities IncreaseDecreaseInOtherNoncurrentLiabilities	799000	USD
CY2018	us-gaap	Increase Decrease In Other Noncurrent Liabilities IncreaseDecreaseInOtherNoncurrentLiabilities	-1478000	USD
CY2019	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	3902000	USD
CY2018	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	5241000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-23966000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	12230000	USD
CY2018	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1138000	USD
CY2020	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	195000	USD
CY2019	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	127000	USD
CY2018	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	18000	USD
CY2020	nhc	Gain Loss On Acquisition Of Equity Method Investment GainLossOnAcquisitionOfEquityMethodInvestment	1707000	USD
CY2019	nhc	Gain Loss On Acquisition Of Equity Method Investment GainLossOnAcquisitionOfEquityMethodInvestment	1975000	USD
CY2018	nhc	Gain Loss On Acquisition Of Equity Method Investment GainLossOnAcquisitionOfEquityMethodInvestment	2050000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	2784000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-0	USD
CY2018	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	1668000	USD
CY2020	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	10593000	USD
CY2019	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-4052000	USD
CY2019	nhc	Increase Decrease In Due To Third Party Payors IncreaseDecreaseInDueToThirdPartyPayors	-1000000	USD
CY2018	nhc	Increase Decrease In Due To Third Party Payors IncreaseDecreaseInDueToThirdPartyPayors	-1281000	USD
CY2020	us-gaap	Increase Decrease In Self Insurance Reserve IncreaseDecreaseInSelfInsuranceReserve	3454000	USD
CY2019	us-gaap	Increase Decrease In Self Insurance Reserve IncreaseDecreaseInSelfInsuranceReserve	540000	USD
CY2018	us-gaap	Increase Decrease In Self Insurance Reserve IncreaseDecreaseInSelfInsuranceReserve	2818000	USD
CY2020	us-gaap	Increase Decrease In Deferred Revenue IncreaseDecreaseInDeferredRevenue	16068000	USD
CY2019	us-gaap	Increase Decrease In Deferred Revenue IncreaseDecreaseInDeferredRevenue	0	USD
CY2018	us-gaap	Increase Decrease In Deferred Revenue IncreaseDecreaseInDeferredRevenue	0	USD
CY2020	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	51253000	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	0	USD
CY2018	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	0	USD
CY2020	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	5898000	USD
CY2019	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	780000	USD
CY2018	us-gaap	Increase Decrease In Other Current Liabilities IncreaseDecreaseInOtherCurrentLiabilities	-2050000	USD
CY2020	us-gaap	Increase Decrease In Other Noncurrent Liabilities IncreaseDecreaseInOtherNoncurrentLiabilities	7146000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-33662000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	4166000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	3923000	USD
CY2018	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	3696000	USD
CY2020	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	203259000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	100103000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	98435000	USD
CY2020	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	21873000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	26400000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	29772000	USD
CY2020	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	6750000	USD
CY2019	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	0	USD
CY2018	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	4300000	USD
CY2020	nhc	Payments For Proceeds From Unconsolidated Investments PaymentsForProceedsFromUnconsolidatedInvestments	305000	USD
CY2019	nhc	Payments For Proceeds From Unconsolidated Investments PaymentsForProceedsFromUnconsolidatedInvestments	222000	USD
CY2018	nhc	Payments For Proceeds From Unconsolidated Investments PaymentsForProceedsFromUnconsolidatedInvestments	444000	USD
CY2020	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	6648000	USD
CY2019	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	15589000	USD
CY2018	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	527000	USD
CY2020	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	425000	USD
CY2019	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	5462000	USD
CY2018	us-gaap	Payments To Acquire Notes Receivable PaymentsToAcquireNotesReceivable	-0	USD
CY2020	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	2483000	USD
CY2019	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	1379000	USD
CY2018	us-gaap	Proceeds From Collection Of Notes Receivable ProceedsFromCollectionOfNotesReceivable	1553000	USD
CY2020	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	84854000	USD
CY2019	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	12471000	USD
CY2018	us-gaap	Payments To Acquire Marketable Securities PaymentsToAcquireMarketableSecurities	13311000	USD
CY2020	us-gaap	Proceeds From Sale Of Restricted Investments ProceedsFromSaleOfRestrictedInvestments	40994000	USD
CY2019	us-gaap	Proceeds From Sale Of Restricted Investments ProceedsFromSaleOfRestrictedInvestments	44500000	USD
CY2018	us-gaap	Proceeds From Sale Of Restricted Investments ProceedsFromSaleOfRestrictedInvestments	4539000	USD
CY2020	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-63878000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-14265000	USD
CY2020	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	40000000	USD
CY2019	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	0	USD
CY2018	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	0	USD
CY2020	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	50000000	USD
CY2019	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	45000000	USD
CY2018	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	45000000	USD
CY2020	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	31921000	USD
CY2019	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	31208000	USD
CY2018	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	29827000	USD
CY2020	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	1756000	USD
CY2019	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	2346000	USD
CY2018	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	2865000	USD
CY2020	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	53000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	872000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	867000	USD
CY2020	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	2488000	USD
CY2019	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	-468000	USD
CY2018	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	0	USD
CY2020	nhc	Entrance Fee Deposits Refunds EntranceFeeDepositsRefunds	7000	USD
CY2019	nhc	Entrance Fee Deposits Refunds EntranceFeeDepositsRefunds	-623000	USD
CY2018	nhc	Entrance Fee Deposits Refunds EntranceFeeDepositsRefunds	-749000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	58699000	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-79748000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-77274000	USD
CY2020	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	97492000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	6090000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-12501000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	61010000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	54920000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	67421000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	158502000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	61010000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	54920000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	147093000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	50334000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	43247000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	11409000	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	10676000	USD
CY2018Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	11673000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	158502000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	61010000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	54920000	USD
CY2020	us-gaap	Interest Paid Net InterestPaidNet	1425000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	3118000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	4899000	USD
CY2020	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	16524000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	20889000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	9182000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	703432000	USD
CY2018	nhc	Noncontrolling Interest Increase From Capital Contribution NoncontrollingInterestIncreaseFromCapitalContribution	750000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-2048000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1778000	USD
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2866000	USD
CY2018	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	867000	USD
CY2018	us-gaap	Dividends Common Stock DividendsCommonStock	30153000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	734457000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	67976000	USD
CY2019	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	468000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	5305000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1878000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2346000	USD
CY2019	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	872000	USD
CY2019	us-gaap	Dividends Common Stock DividendsCommonStock	31553000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	779069000	USD
CY2020	us-gaap	Profit Loss ProfitLoss	41990000	USD
CY2020	nhc	Noncontrolling Interest Increase From Capital Contribution NoncontrollingInterestIncreaseFromCapitalContribution	2488000	USD
CY2020	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	2497000	USD
CY2020	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	2453000	USD
CY2020	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	1756000	USD
CY2020	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	53000	USD
CY2020	us-gaap	Dividends Common Stock DividendsCommonStock	31940000	USD
CY2020Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	798260000	USD
CY2020	us-gaap	Use Of Estimates UseOfEstimates	<p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"><i>Use of Estimates</i></p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"> </p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify; text-indent: 36pt;">The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates and could cause our reported net income to vary significantly from period to period, including but <em style="font: inherit;">not</em> limited to, the potential future effects of the novel coronavirus (“COVID-<em style="font: inherit;">19”</em>).</p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"> </p>
CY2020	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	3339000	USD
CY2019	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	2403000	USD
CY2018	us-gaap	Provision For Doubtful Accounts ProvisionForDoubtfulAccounts	1524000	USD
CY2020Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	5672000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	4451000	USD
CY2020	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	31983000	USD
CY2019	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	24758000	USD
CY2018	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	28710000	USD
CY2020Q4	us-gaap	Contract With Customer Refund Liability ContractWithCustomerRefundLiability	7462000	USD
CY2019Q4	us-gaap	Contract With Customer Refund Liability ContractWithCustomerRefundLiability	7455000	USD
CY2020Q4	us-gaap	Continuing Care Retirement Communities Advance Fees Obligation For Future Services Amount ContinuingCareRetirementCommunitiesAdvanceFeesObligationForFutureServicesAmount	2177000	USD
CY2019Q4	us-gaap	Continuing Care Retirement Communities Advance Fees Obligation For Future Services Amount ContinuingCareRetirementCommunitiesAdvanceFeesObligationForFutureServicesAmount	2035000	USD
CY2020	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"><i>Concentration of Credit Risks</i></p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"> </p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify; text-indent: 36pt;">Our credit risks primarily relate to cash and cash equivalents, restricted cash and cash equivalents, accounts receivable, marketable securities, restricted marketable securities and notes receivable. Cash and cash equivalents are primarily held in bank accounts and overnight investments. Restricted cash and cash equivalents are primarily invested in commercial paper and certificates of deposit with financial institutions and other interest-bearing accounts. Accounts receivable consist primarily of amounts due from patients (funded through Medicare, Medicaid, other contractual programs and through private payors) and from other health care companies for management, accounting and other services. We perform continual credit evaluations of our clients and maintain appropriate allowances for doubtful accounts on any accounts receivable proving uncollectible, and continually monitor and adjust these allowances as necessary. Marketable securities and restricted marketable securities are held primarily in accounts with brokerage institutions. Notes receivable relate primarily to secured loans with health care facilities.</p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"> </p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify; text-indent: 36pt;">At any point in time we have funds in our operating accounts and restricted cash accounts that are with <em style="font: inherit;">third</em> party financial institutions. These balances in the U.S. <em style="font: inherit;"> may </em>exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance limits. While we monitor the cash balances in our operating accounts, these cash and restricted cash balances could be impacted if the underlying financial institutions fail or could be subject to other adverse conditions in the financial markets.</p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"> </p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify; text-indent: 36pt;">Our financial instruments, principally our notes receivable, are subject to the possibility of loss of the carrying values as a result of the failure of other parties to perform according to their contractual obligations. We obtain various collateral and other protective rights, and continually monitor these rights in order to reduce such possibilities of credit loss. We evaluate the need to provide reserves for potential credit losses on our financial instruments based on management's periodic review of the portfolio on an instrument-by-instrument basis.</p> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin: 0pt; text-align: justify;"> </p>
	nhc	Proceeds From Government Assistance Cares Act ProceedsFromGovernmentAssistanceCaresAct	63573000	USD
CY2020	nhc	Government Assistance Stimulus Income Cares Act GovernmentAssistanceStimulusIncomeCaresAct	47505000	USD
CY2020Q4	nhc	Provider Relief Funds ProviderReliefFunds	16068000	USD
CY2020	nhc	Proceeds From Medicare Accelerated And Advance Payment Program ProceedsFromMedicareAcceleratedAndAdvancePaymentProgram	51253000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	931795000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	947872000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	932774000	USD
CY2020	nhc	Revenue From Contract With Customer Including Assessed Tax Percentage RevenueFromContractWithCustomerIncludingAssessedTaxPercentage	1	pure
CY2019	nhc	Revenue From Contract With Customer Including Assessed Tax Percentage RevenueFromContractWithCustomerIncludingAssessedTaxPercentage	1	pure
CY2018	nhc	Revenue From Contract With Customer Including Assessed Tax Percentage RevenueFromContractWithCustomerIncludingAssessedTaxPercentage	1	pure
CY2020Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	51253000	USD
CY2019Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	0	USD
CY2020	nhc	Proceeds From Government Assistance Medicare Accelerated And Advance Payment Program ProceedsFromGovernmentAssistanceMedicareAcceleratedAndAdvancePaymentProgram	51253000	USD
CY2020Q4	us-gaap	Contract With Customer Liability Current ContractWithCustomerLiabilityCurrent	51253000	USD
CY2020	us-gaap	Insurance Services Revenue InsuranceServicesRevenue	5447000	USD
CY2019	us-gaap	Insurance Services Revenue InsuranceServicesRevenue	6209000	USD
CY2018	us-gaap	Insurance Services Revenue InsuranceServicesRevenue	7084000	USD
CY2020	nhc	Miscellaneous Revenue MiscellaneousRevenue	771000	USD
CY2019	nhc	Miscellaneous Revenue MiscellaneousRevenue	1128000	USD
CY2018	nhc	Miscellaneous Revenue MiscellaneousRevenue	1386000	USD
CY2020	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	2784000	USD
CY2019	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	0	USD
CY2020	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	22768000	USD
CY2019	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	22641000	USD
CY2018	us-gaap	Operating Leases Income Statement Lease Revenue OperatingLeasesIncomeStatementLeaseRevenue	22262000	USD
CY2020	nhc	Management And Accounting Services Fees Revenue ManagementAndAccountingServicesFeesRevenue	17147000	USD
CY2019	nhc	Management And Accounting Services Fees Revenue ManagementAndAccountingServicesFeesRevenue	18533000	USD
CY2018	nhc	Management And Accounting Services Fees Revenue ManagementAndAccountingServicesFeesRevenue	15175000	USD
CY2018	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	1668000	USD
CY2020	nhc	Other Revenues OtherRevenues	48917000	USD
CY2019	nhc	Other Revenues OtherRevenues	48511000	USD
CY2018	nhc	Other Revenues OtherRevenues	47575000	USD
CY2020	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	22019000	USD
CY2019	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	21937000	USD
CY2018	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	21516000	USD
CY2020	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	749000	USD
CY2019	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	704000	USD
CY2018	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	746000	USD
CY2020	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	22768000	USD
CY2019	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	22641000	USD
CY2018	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	22262000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Next Twelve Months LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths	23011000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Two Years LessorOperatingLeasePaymentsToBeReceivedTwoYears	22907000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Three Years LessorOperatingLeasePaymentsToBeReceivedThreeYears	22738000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Four Years LessorOperatingLeasePaymentsToBeReceivedFourYears	22730000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Five Years LessorOperatingLeasePaymentsToBeReceivedFiveYears	22730000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received Thereafter LessorOperatingLeasePaymentsToBeReceivedThereafter	220000	USD
CY2018	us-gaap	Revenues Revenues	980349000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	26747000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	12230000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	88015000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	932774000	USD
CY2018	nhc	Other Revenues OtherRevenues	47575000	USD
CY2020Q4	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	114336000	USD
CY2020Q4	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	6750000	USD
CY2018Q4	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	4300000	USD
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	9744000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	1020000	USD
CY2020	nhc	Dividends And Other Net Realized Gains And Losses On Sales Of Securities DividendsAndOtherNetRealizedGainsAndLossesOnSalesOfSecurities	8390000	USD
CY2019	nhc	Dividends And Other Net Realized Gains And Losses On Sales Of Securities DividendsAndOtherNetRealizedGainsAndLossesOnSalesOfSecurities	7840000	USD
CY2018	nhc	Dividends And Other Net Realized Gains And Losses On Sales Of Securities DividendsAndOtherNetRealizedGainsAndLossesOnSalesOfSecurities	7417000	USD
CY2020	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	5795000	USD
CY2019	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	7188000	USD
CY2018	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	7183000	USD
CY2020	nhc	Gain Loss On Acquisition Of Equity Method Investment GainLossOnAcquisitionOfEquityMethodInvestment	1707000	USD
CY2019	nhc	Gain Loss On Acquisition Of Equity Method Investment GainLossOnAcquisitionOfEquityMethodInvestment	1975000	USD
CY2018	nhc	Gain Loss On Acquisition Of Equity Method Investment GainLossOnAcquisitionOfEquityMethodInvestment	2050000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	28234000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	26747000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	17670000	USD
CY2020	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	931795000	USD
CY2020	nhc	Other Revenues OtherRevenues	48917000	USD
CY2020	nhc	Government Assistance Stimulus Income Cares Act GovernmentAssistanceStimulusIncomeCaresAct	47505000	USD
CY2020	us-gaap	Revenues Revenues	1028217000	USD
CY2020	us-gaap	Labor And Related Expense LaborAndRelatedExpense	609306000	USD
CY2020	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	286845000	USD
CY2020	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	40494000	USD
CY2020	us-gaap	Depreciation And Amortization DepreciationAndAmortization	42018000	USD
CY2020	us-gaap	Interest Expense InterestExpense	1399000	USD
CY2020	us-gaap	Costs And Expenses CostsAndExpenses	980062000	USD
CY2020	us-gaap	Operating Income Loss OperatingIncomeLoss	48155000	USD
CY2020	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	28234000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-23966000	USD
CY2020	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	52423000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	947872000	USD
CY2019	nhc	Other Revenues OtherRevenues	48511000	USD
CY2019	us-gaap	Revenues Revenues	996383000	USD
CY2019	us-gaap	Labor And Related Expense LaborAndRelatedExpense	592831000	USD
CY2019	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	268442000	USD
CY2019	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	40518000	USD
CY2019	us-gaap	Depreciation And Amortization DepreciationAndAmortization	42419000	USD
CY2019	us-gaap	Interest Expense InterestExpense	3135000	USD
CY2019	us-gaap	Costs And Expenses CostsAndExpenses	947345000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	49038000	USD
CY2018	us-gaap	Labor And Related Expense LaborAndRelatedExpense	582721000	USD
CY2018	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	254038000	USD
CY2018	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	40923000	USD
CY2018	us-gaap	Depreciation And Amortization DepreciationAndAmortization	41894000	USD
CY2018	us-gaap	Interest Expense InterestExpense	4697000	USD
CY2018	us-gaap	Costs And Expenses CostsAndExpenses	924273000	USD
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	56076000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	17670000	USD
CY2018	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1138000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	74884000	USD
CY2013Q3	nhc	Facility Purchase Price FacilityPurchasePrice	49000000	USD
CY2020Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	12293000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	16173000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	179055000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	202909000	USD
CY2020Q4	nhc	Lease Rightofuse Asset LeaseRightofuseAsset	191348000	USD
CY2019Q4	nhc	Lease Rightofuse Asset LeaseRightofuseAsset	219082000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	4423000	USD
CY2019Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	4166000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	25451000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	24243000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	10540000	USD
CY2019Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	14963000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	153604000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	178666000	USD
CY2020Q4	nhc	Lease Liability LeaseLiability	194018000	USD
CY2019Q4	nhc	Lease Liability LeaseLiability	222038000	USD
CY2020Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P3Y2M12D
CY2019Q4	us-gaap	Finance Lease Weighted Average Remaining Lease Term1 FinanceLeaseWeightedAverageRemainingLeaseTerm1	P4Y2M12D
CY2020Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P6Y2M12D
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P7Y1M6D
CY2020Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.060	pure
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	1050000	USD
CY2020	nhc	Total Operating Lease Cost TotalOperatingLeaseCost	40494000	USD
CY2019	nhc	Total Operating Lease Cost TotalOperatingLeaseCost	40518000	USD
CY2020	us-gaap	Lease Cost LeaseCost	45464000	USD
CY2019	us-gaap	Lease Cost LeaseCost	45713000	USD
CY2019Q4	us-gaap	Finance Lease Weighted Average Discount Rate Percent FinanceLeaseWeightedAverageDiscountRatePercent	0.060	pure
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.060	pure
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.060	pure
CY2020	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	3906000	USD
CY2019	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	3889000	USD
CY2020	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1064000	USD
CY2019	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1306000	USD
CY2020	nhc	Finance Lease Cost FinanceLeaseCost	4970000	USD
CY2019	nhc	Finance Lease Cost FinanceLeaseCost	5195000	USD
CY2020	us-gaap	Operating Lease Cost OperatingLeaseCost	35656000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	35881000	USD
CY2020	us-gaap	Variable Lease Cost VariableLeaseCost	3617000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	3587000	USD
CY2020	us-gaap	Short Term Lease Cost ShortTermLeaseCost	1221000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Next Twelve Months FinanceLeaseLiabilityPaymentsDueNextTwelveMonths	5200000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	35292000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	5200000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	34971000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	5200000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	34613000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	867000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	34414000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	0	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	34253000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due After Year Five FinanceLeaseLiabilityPaymentsDueAfterYearFive	0	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	39950000	USD
CY2020Q4	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	16467000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	213493000	USD
CY2020Q4	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	1504000	USD
CY2020Q4	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	34438000	USD
CY2020Q4	us-gaap	Finance Lease Liability FinanceLeaseLiability	14963000	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	179055000	USD
CY2020Q4	us-gaap	Finance Lease Liability Current FinanceLeaseLiabilityCurrent	4423000	USD
CY2020Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	25451000	USD
CY2020Q4	us-gaap	Finance Lease Liability Noncurrent FinanceLeaseLiabilityNoncurrent	10540000	USD
CY2020Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	153604000	USD
CY2020	us-gaap	Operating Lease Payments OperatingLeasePayments	35655000	USD
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	35881000	USD
CY2020	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	1064000	USD
CY2019	us-gaap	Finance Lease Interest Payment On Liability FinanceLeaseInterestPaymentOnLiability	1306000	USD
CY2020	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	4166000	USD
CY2019	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	3923000	USD
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15306174
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15270154
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15224886
CY2020	us-gaap	Net Income Loss NetIncomeLoss	41871000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	68211000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	58964000	USD
CY2020	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.74
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	4.47
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	3.87
CY2020	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15306174
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15270154
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	15224886
CY2020	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	15369523
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	15360046
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	15236826
CY2020	us-gaap	Net Income Loss NetIncomeLoss	41871000	USD
CY2019	us-gaap	Net Income Loss NetIncomeLoss	68211000	USD
CY2018	us-gaap	Net Income Loss NetIncomeLoss	58964000	USD
CY2020	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.72
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	4.44
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	3.87
CY2020Q4	nhc	Marketable Securities Availableforsale Amortized Cost MarketableSecuritiesAvailableforsaleAmortizedCost	218396000	USD
CY2020Q4	us-gaap	Marketable Securities MarketableSecurities	323105000	USD
CY2019Q4	nhc	Marketable Securities Availableforsale Amortized Cost MarketableSecuritiesAvailableforsaleAmortizedCost	174342000	USD
CY2019Q4	us-gaap	Marketable Securities MarketableSecurities	299859000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	49694000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	49863000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	15726000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	15767000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	99143000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	103002000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	88314000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	90408000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	34326000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	36685000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	40126000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	41231000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	274000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	285000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	0	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	0	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	183437000	USD
CY2020Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	189835000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	144166000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	147406000	USD
CY2020Q4	nhc	Equity Securities Fv Ni Gross Unrealized Gain EquitySecuritiesFvNiGrossUnrealizedGain	98445000	USD
CY2019Q4	nhc	Equity Securities Fv Ni Gross Unrealized Gain EquitySecuritiesFvNiGrossUnrealizedGain	122290000	USD
CY2020Q4	nhc	Equity Securities Fv Ni Gross Unrealized Loss EquitySecuritiesFvNiGrossUnrealizedLoss	134000	USD
CY2019Q4	nhc	Equity Securities Fv Ni Gross Unrealized Loss EquitySecuritiesFvNiGrossUnrealizedLoss	13000	USD
CY2020	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-23966000	USD
CY2019	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	12230000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	6759000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	3407000	USD
CY2020Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	361000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	137000	USD
CY2020	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	40994000	USD
CY2019	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	44500000	USD
CY2018	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	4539000	USD
CY2020	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	195000	USD
CY2019	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	127000	USD
CY2018	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	18000	USD
CY2020Q4	us-gaap	Land Land	64385000	USD
CY2019Q4	us-gaap	Land Land	61018000	USD
CY2020Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	125889000	USD
CY2019Q4	us-gaap	Leasehold Improvements Gross LeaseholdImprovementsGross	122520000	USD
CY2020Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	641367000	USD
CY2019Q4	us-gaap	Buildings And Improvements Gross BuildingsAndImprovementsGross	644236000	USD
CY2020Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	180463000	USD
CY2019Q4	us-gaap	Furniture And Fixtures Gross FurnitureAndFixturesGross	177717000	USD
CY2020Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	18322000	USD
CY2019Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	11713000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1030426000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	1017204000	USD
CY2020Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	510108000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	481774000	USD
CY2020Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	520318000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	535430000	USD
CY2020Q4	nhc	Cost To Complete Construction In Progress CostToCompleteConstructionInProgress	380000	USD
CY2020Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	13021000	USD
CY2019Q4	us-gaap	Notes Receivable Gross NotesReceivableGross	15079000	USD
CY2020	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	19054000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	13356000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	13583000	USD
CY2020	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	2337000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1101000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1612000	USD
CY2020	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	21391000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	14457000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	15195000	USD
CY2020	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-8349000	USD
CY2019	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	4048000	USD
CY2018	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	610000	USD
CY2020	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2609000	USD
CY2019	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	1534000	USD
CY2018	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	380000	USD
CY2020	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-10958000	USD
CY2020	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	1631000	USD
CY2019Q4	nhc	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	52870000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	698000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	665000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	69154000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	71143000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	-0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	-0	USD
CY2020Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	69154000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	5582000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	990000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10433000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	20039000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16185000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	1764000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Reserves DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsReserves	1625000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	11803000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	5926000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	4125000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Other DeferredTaxAssetsTaxDeferredExpenseOther	3966000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	1063000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost	666000	USD
CY2020Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	4215000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	5425000	USD
CY2020Q4	nhc	Deferred Tax Assets Operating Lease Liabilities DeferredTaxAssetsOperatingLeaseLiabilities	45486000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	71143000	USD
CY2020Q4	nhc	Deferred Tax Liabilities Unrealized Gains On Marketable Securities DeferredTaxLiabilitiesUnrealizedGainsOnMarketableSecurities	27040000	USD
CY2019Q4	nhc	Deferred Tax Liabilities Unrealized Gains On Marketable Securities DeferredTaxLiabilitiesUnrealizedGainsOnMarketableSecurities	32638000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2042000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2094000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	2360000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Goodwill And Intangible Assets Intangible Assets DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets	2063000	USD
CY2020Q4	nhc	Deferred Tax Liabilities Book Basis In Excess Of Tax Basis Of Securities DeferredTaxLiabilitiesBookBasisInExcessOfTaxBasisOfSecurities	2514000	USD
CY2019Q4	nhc	Deferred Tax Liabilities Book Basis In Excess Of Tax Basis Of Securities DeferredTaxLiabilitiesBookBasisInExcessOfTaxBasisOfSecurities	2172000	USD
CY2020Q4	nhc	Deferred Tax Liabilities Long Term Investments DeferredTaxLiabilitiesLongTermInvestments	3791000	USD
CY2019Q4	nhc	Deferred Tax Liabilities Long Term Investments DeferredTaxLiabilitiesLongTermInvestments	3318000	USD
CY2020Q4	nhc	Deferred Tax Liabilities Operating Lease Assets DeferredTaxLiabilitiesOperatingLeaseAssets	45486000	USD
CY2019Q4	nhc	Deferred Tax Liabilities Operating Lease Assets DeferredTaxLiabilitiesOperatingLeaseAssets	52870000	USD
CY2020Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	83233000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	95155000	USD
CY2020Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	14079000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	24012000	USD
CY2020	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	11009000	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	18483000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	15726000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	3850000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	3213000	USD
CY2020	nhc	Income Tax Reconciliation Return To Provision IncomeTaxReconciliationReturnToProvision	382000	USD
CY2019	nhc	Income Tax Reconciliation Return To Provision IncomeTaxReconciliationReturnToProvision	793000	USD
CY2018	nhc	Income Tax Reconciliation Return To Provision IncomeTaxReconciliationReturnToProvision	1418000	USD
CY2020	us-gaap	Income Tax Reconciliation Tax Contingencies IncomeTaxReconciliationTaxContingencies	166000	USD
CY2019	us-gaap	Income Tax Reconciliation Tax Contingencies IncomeTaxReconciliationTaxContingencies	512000	USD
CY2018	us-gaap	Income Tax Reconciliation Tax Contingencies IncomeTaxReconciliationTaxContingencies	586000	USD
CY2020	nhc	Income Tax Reconciliation Expiration Of Statute Of Limitations IncomeTaxReconciliationExpirationOfStatuteOfLimitations	2366000	USD
CY2019	nhc	Income Tax Reconciliation Expiration Of Statute Of Limitations IncomeTaxReconciliationExpirationOfStatuteOfLimitations	2064000	USD
CY2018	nhc	Income Tax Reconciliation Expiration Of Statute Of Limitations IncomeTaxReconciliationExpirationOfStatuteOfLimitations	2222000	USD
CY2020	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	375000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	51000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	300000	USD
CY2020	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	-576000	USD
CY2019	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	1556000	USD
CY2018	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	459000	USD
CY2020	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10433000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	20039000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	16185000	USD
CY2020	us-gaap	Unrecognized Tax Benefits Period Increase Decrease UnrecognizedTaxBenefitsPeriodIncreaseDecrease	-1812000	USD
CY2020	nhc	Effective Income Tax Rate Reconciliation Benefit Resulting From Expiration Of Applicable Statute Limitations Amount EffectiveIncomeTaxRateReconciliationBenefitResultingFromExpirationOfApplicableStatuteLimitationsAmount	2366000	USD
CY2020	nhc	Unrecognized Tax Benefits Reduction Resulting From Cares Act UnrecognizedTaxBenefitsReductionResultingFromCARESAct	2273000	USD
CY2018	nhc	Effective Income Tax Rate Reconciliation Benefit Resulting From Expiration Of Applicable Statute Limitations Amount EffectiveIncomeTaxRateReconciliationBenefitResultingFromExpirationOfApplicableStatuteLimitationsAmount	2222000	USD
CY2020Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	4727000	USD
CY2020Q4	us-gaap	Significant Change In Unrecognized Tax Benefits Is Reasonably Possible Amount Of Unrecorded Benefit SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit	2286000	USD
CY2020	us-gaap	Income Tax Examination Penalties And Interest Expense IncomeTaxExaminationPenaltiesAndInterestExpense	-695000	USD
CY2019	us-gaap	Income Tax Examination Penalties And Interest Expense IncomeTaxExaminationPenaltiesAndInterestExpense	38000	USD
CY2018	us-gaap	Income Tax Examination Penalties And Interest Expense IncomeTaxExaminationPenaltiesAndInterestExpense	-4000	USD
CY2020	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2453000	USD
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1878000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	1778000	USD
CY2020	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	677000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3918000	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	1047000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	677000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	3960000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	1047000	USD
CY2020Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	2581000	USD
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0087	pure
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0230	pure
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0246	pure
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.201	pure
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.174	pure
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.161	pure
CY2020	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P2Y2M12D
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P2Y3M18D
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P3Y
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0291	pure
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0273	pure
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0329	pure
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1239407
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	71.19
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	110265
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	61.39
CY2018	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	68291
CY2018	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	54.31
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	118000
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	72.11
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	1163381
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	71.16
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	77316
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	77.89
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	346168
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	71.57
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	85000
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	72.94
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	809529
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	71.24
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	104057
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	73.98
CY2020	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	43630
CY2020	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	63.37
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	3000
CY2020	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	72.94
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	866956
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	72.11
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	572790	USD
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	215456
CY2020Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	68.35
CY2020Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	572790	USD
CY2020Q4	us-gaap	Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Number Of Outstanding Options ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions	866956
CY2020Q4	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Exercise Price Beginning Balance1 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1	72.11
CY2020	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Term2 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2	P1Y3M18D
CY2020Q4	us-gaap	Self Insurance Reserve SelfInsuranceReserve	99537000	USD
CY2019Q4	us-gaap	Self Insurance Reserve SelfInsuranceReserve	96011000	USD
CY2010Q4	us-gaap	Notes And Loans Receivable Gross Current NotesAndLoansReceivableGrossCurrent	4500000	USD
CY2020	us-gaap	Increase Decrease In Notes Payable Current IncreaseDecreaseInNotesPayableCurrent	11047000	USD
CY2019	us-gaap	Increase Decrease In Notes Payable Current IncreaseDecreaseInNotesPayableCurrent	11047000	USD

Files In Submission

Name	View Source	Status
0001437749-21-003415-index-headers.html	Edgar Link	pending
0001437749-21-003415-index.html	Edgar Link	pending
0001437749-21-003415.txt	Edgar Link	pending
0001437749-21-003415-xbrl.zip	Edgar Link	pending
ex_225369.htm	Edgar Link	pending
ex_225370.htm	Edgar Link	pending
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ex_225383.htm	Edgar Link	pending
ex_225661.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
graph1.jpg	Edgar Link	pending
lbmc.jpg	Edgar Link	pending
lbmcsig.jpg	Edgar Link	pending
logobanner.jpg	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
nhc-20201231.xsd	Edgar Link	pending
nhc-20201231_cal.xml	Edgar Link	unprocessable
nhc-20201231_def.xml	Edgar Link	unprocessable
nhc-20201231_lab.xml	Edgar Link	unprocessable
nhc-20201231_pre.xml	Edgar Link	unprocessable
nhc20201231_10k.htm	Edgar Link	pending
nhc20201231_10k_htm.xml	Edgar Link	completed
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report.css	Edgar Link	pending
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$NHC
NATIONAL HEALTHCARE CORP Stock $nhc

2020 Q4 Form 10-K Financial Statement

#000143774921003415 Filed on February 19, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NHC NATIONAL HEALTHCARE CORP Stock $nhc

2020 Q4 Form 10-K Financial Statement

#000143774921003415 Filed on February 19, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$NHC
NATIONAL HEALTHCARE CORP Stock $nhc