The initial rate charged under a lease entered into in connection with the purchase of a property.

No definition available.

Name:	nhi_InitialLeaseRate
Namespace Prefix:	nhi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The initial escalator rate charged from lease year 3 through the end of the lease term under a lease entered into in connection with the purchase of a property.

+ References

No definition available.

+ Details

Name:	nhi_LeaseEscalatorRateAfterLeaseYear3
Namespace Prefix:	nhi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The initial lease escalator rate charged from lease year 2 through lease year 4 under a lease entered into in connection with the purchase of a property.

+ References

No definition available.

+ Details

Name:	nhi_LeaseEscalatorRateLeaseYear2toLeaseYear4
Namespace Prefix:	nhi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The initial lease escalator to be charged starting after lease year 4 under a lease entered into in connection with the purchase of a property.

+ References

No definition available.

+ Details

Name:	nhi_LeaseEscalatorRateafterLeaseYear4
Namespace Prefix:	nhi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents a lessee's payment to acquire a purchase option.

+ References

No definition available.

+ Details

Name:	nhi_LesseePaymentToAcquirePurchaseOption
Namespace Prefix:	nhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This item represents the number of shares of a lessor that are owned by a significant lessee as of the end of the reporting period.

+ References

No definition available.

+ Details

Name:	nhi_LessorEquitySharesOwnedSignificantLessee
Namespace Prefix:	nhi_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the minimum annual lease income to be received.

+ References

No definition available.

+ Details

Name:	nhi_MinimumAnnualLeaseIncome
Namespace Prefix:	nhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the original cost of corporate assets that are not part of the investment portfolio.

+ References

No definition available.

+ Details

Name:	nhi_NonportfolioAssetsOriginalCost
Namespace Prefix:	nhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number Of Additional Lease Renewal Options

+ References

No definition available.

+ Details

Name:	nhi_NumberOfAdditionalLeaseRenewalOptions
Namespace Prefix:	nhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of lessees of real estate property at the end of the period.

+ References

No definition available.

+ Details

Name:	nhi_NumberOfLessees
Namespace Prefix:	nhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Real Estate Properties Acquired

+ References

No definition available.

+ Details

Name:	nhi_NumberOfRealEstatePropertiesAcquired
Namespace Prefix:	nhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Master Leases

+ References

No definition available.

+ Details

Name:	nhi_NumberofMasterLeases
Namespace Prefix:	nhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the percentage of income recognized from a lease tenant.

+ References

No definition available.

+ Details

Name:	nhi_PercentageOfContinuingRevenue
Namespace Prefix:	nhi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the rental revenue rate earned during the period from lessee-operators based on revenues generated in their operations, generally in excess of a base amount. Generally stipulated in the lease agreement, it usually will provide for a fixed percentage of revenue to be paid as additional (or possibly only) rent due the lessor, and may be based on gross revenues, net revenues, or multiple variations thereof.

+ References

No definition available.

+ Details

Name:	nhi_PercentageRentRate
Namespace Prefix:	nhi_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents the amount of an outstanding purchase option.

+ References

No definition available.

+ Details

Name:	nhi_PurchaseOptionAmount
Namespace Prefix:	nhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The element represents the original cost of all portfolio leased assets.

+ References

No definition available.

+ Details

Name:	nhi_RealEstateInvestmentPropertyPortfolioAssets
Namespace Prefix:	nhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the number of real estate properties for which the entity has made a binding commitment to purchase.

+ References

No definition available.

+ Details

Name:	nhi_RealEstatePropertiesCommitmentToPurchase
Namespace Prefix:	nhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the purchase commitment for real estate properties which the entity has entered into a binding agreement to acquire.

+ References

No definition available.

+ Details

Name:	nhi_RealEstatePropertiesCommitmentToPurchaseAmount
Namespace Prefix:	nhi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cumulative difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property, by the lessor or lessee, respectively. Such receivable is reduced by allowances attributable to, for instance, credit risk associated with a lessee.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 35
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=77913719&loc=d3e40879-112712

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39927-112707

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39896-112707

+ Details

Name:	us-gaap_DeferredRentReceivablesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Term of the lessor's leasing arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

Term of the lessor's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39896-112707

+ Details

Name:	us-gaap_OperatingLeasesIncomeStatementLeaseRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow from the acquisition of a piece of land, anything permanently fixed to it, including buildings, structures on it and so forth; includes real estate intended to generate income for the owner; excludes real estate acquired for use by the owner.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Difference between actual rental income due and rental income recognized on a straight-line basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_StraightLineRent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_MajorCustomersAxis=nhi_HolidayAcquisitionHoldingsMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=nhi_NationalHealthcareCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=nhi_NHC1991LeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=nhi_NHC2013LeaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=nhi_BickfordSeniorLivingMember
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Data Type:	na
Balance Type:
Period Type:

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Name:	us-gaap_MajorCustomersAxis=nhi_SeniorLivingCommunitiesMember
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Data Type:	na
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Name:	us-gaap_MajorCustomersAxis=nhi_DefaultTenantMember
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=nhi_SeniorHousingCommunityMember
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Data Type:	na
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Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=nhi_SkilledNursingFacilityMember
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Data Type:	na
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Real Estate (Narrative) (Details)	1 Months Ended	3 Months Ended
Real Estate (Narrative) (Details)	Jan. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) properties beds_or_units renewalOptions Master_Leases shares	Mar. 31, 2017 USD ($)	Jan. 12, 2018 beds_or_units	Dec. 31, 2017 USD ($) properties	Sep. 30, 2017 USD ($)
Number of Real Estate Properties \| properties					210
Number of States in which Entity Operates					32
Nonportfolio Assets, Original Cost					$ 1,298,000
Real Estate Investment Property, Portfolio Assets						$ 2,682,387,000
Number of Lessees					27
Payments to Acquire Real Estate		$ 14,404,000	$ 118,011,000
Lessee Payment To Acquire Purchase Option		1,275,000	1,250,000
Operating Leases, Income Statement, Lease Revenue		69,253,000	63,127,000
Deferred Rent Receivables, Net		102,046,000			$ 97,359,000
Straight Line Rent		5,962,000	5,755,000
Real Estate Properties, Commitment To Purchase, Amount		$ 47,017,000
Holiday Acquisition Holdings [Member]
Number of Real Estate Properties \| properties		25
Lessor, Operating Lease, Term of Contract		17 years
Lease Escalator Rate, After Lease Year 3		3.50%
Operating Leases, Income Statement, Lease Revenue		$ 10,954,000	$ 10,954,000
Percentage of Continuing Revenue		15.00%	17.00%
Straight Line Rent		$ 1,530,000	$ 1,849,000
National Healthcare Corporation [Member]
Number of Real Estate Properties \| properties		42
Number of Master Leases \| Master_Leases		2
Operating Leases, Income Statement, Lease Revenue		$ 9,674,000	$ 9,513,000
Percentage of Continuing Revenue		13.00%	14.00%
Lessor Equity Shares Owned, Significant Lessee \| shares		1,630,462
National Healthcare Corporation [Member] \| NHC - 1991 Lease [Member]
Number of Real Estate Properties \| properties		35
Number Of Additional Lease Renewal Options \| renewalOptions		2
Lease Renewal Period In Years		5 years
Percentage Rent Rate		0.04
Minimum Annual Lease Income		$ 30,750,000
National Healthcare Corporation [Member] \| NHC - 2013 Lease [Member]
Number Of Real Estate Properties Acquired \| properties		7
Percentage Rent Rate		0.04
Minimum Annual Lease Income		$ 3,450,000
Purchase Option Amount		$ 49,000,000
Bickford Senior Living [Member]
Number of Real Estate Properties \| properties		47
Operating Leases, Income Statement, Lease Revenue		$ 11,445,000	$ 9,373,000
Percentage of Continuing Revenue		16.00%	14.00%
Straight Line Rent		$ 1,169,000	$ 910,000
Minimum Annual Lease Income		$ 41,942,000
Senior Living Communities [Member]
Number of Real Estate Properties \| properties		9
Number of Units in Real Estate Property		1,970
Lessor, Operating Lease, Term of Contract		15 years
Lease Escalator Rate Lease Year 2 to Lease Year 4		4.00%
Lease Escalator Rate after Lease Year 4		3.00%
Operating Leases, Income Statement, Lease Revenue		$ 11,449,000	$ 11,431,000
Percentage of Continuing Revenue		16.00%	17.00%
Straight Line Rent		$ 1,359,000	$ 1,746,000
Number Of Additional Lease Renewal Options		2
Lease Renewal Period In Years		5 years
Ensign Group [Member]
Real Estate Properties, Commitment To Purchase \| properties		2
Default Tenant [Member]
Percentage of Continuing Revenue		4.00%
Deferred Rent Receivables, Net		$ 3,773,000
Senior Housing Community [Member]
Number of Real Estate Properties \| properties					136
Skilled Nursing Facility [Member]
Number of Real Estate Properties \| properties					69
Skilled Nursing Facility [Member] \| National Healthcare Corporation [Member]
Number of Real Estate Properties \| properties		39
Skilled Nursing Facility [Member] \| National Healthcare Corporation [Member] \| Subleased Facilities [Member]
Number of Real Estate Properties \| properties		4
Hospital [Member]
Number of Real Estate Properties \| properties					3
Medical Office Building [Member]
Number of Real Estate Properties \| properties					2
Independent Living Facility [Member] \| National Healthcare Corporation [Member]
Number of Real Estate Properties \| properties		3
Ensign Waxahachie Purchase [Member]
Number of Units in Real Estate Property \| beds_or_units				121
Payments to Acquire Real Estate	$ 14,404,000
Lessee Payment To Acquire Purchase Option	$ 1,275,000
Lessor, Operating Lease, Term of Contract	13 years
Initial lease rate				8.20%