Note 16 - Long-term Debt (Details Textual) - July 2026 Credit Agreement [Member]	May 26, 2026 USD ($)
Debt Instrument, Term (Year)	5 years
Debt Instrument, Periodic Payment	$ 5,938,000
Minimum [Member]
Debt Instrument, Interest Rate, Base Rate	1.00%
Line of Credit Facility, Commitment Fee Percentage	0.20%
Maximum [Member]
Line of Credit Facility, Commitment Fee Percentage	0.30%
Secured Overnight Financing Rate (SOFR) [Member]
Debt Instrument, Interest Rate, Base Rate	1.00%
Debt Instrument, Funding Day Interest Rate	1.50%
Secured Overnight Financing Rate (SOFR) [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Secured Overnight Financing Rate (SOFR) [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Base Rate [Member]
Debt Instrument, Funding Day Interest Rate	0.50%
Base Rate [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Base Rate [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate	0.75%
Federal Funds Rate [Member]
Debt Instrument, Interest Rate, Base Rate	0.50%
Term Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 475,000,000
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 75,000,000

The interest rate at funding day for the debt instrument.

No definition available.

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Namespace Prefix:	nhc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The interest rates used in determining the base rate.

+ References

No definition available.

+ Details

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Namespace Prefix:	nhc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(a)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period between issuance and maturity of debt instrument, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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- Details

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