Debt (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011 years properties	Jun. 30, 2011 years properties	Jun. 30, 2010	Dec. 31, 2010
Debt
Line of Credit Facility, Maximum Borrowing Capacity	$ 100,000,000	$ 100,000,000
Unsecured revolving credit facility	50,000,000	50,000,000
Revolving credit facility term	3	3
Revolving credit facility interest rate	2.81%	2.81%
Increase in total credit facility		200,000,000
Borrowings on term loan		50,000,000	0
Derivative, Fixed Interest Rate	3.98%	3.98%
Loan for quarterly principal payments		625,000
Debt	48,750,000	48,750,000		37,765,000
Unused balance of the unsecured revolving credit facility	50,000,000	50,000,000
Interest Expense		1,037,000
Amortization of loan costs		77,000
Increase in fair value of interest rate swap agreement	$ (988,000)	$ 266,000	$ 0

This item represents the amount to which the credit facility could be expanded if an attached accordion feature is exercised.

Name:	nhi_IncreaseInTotalCreditFacility
Namespace Prefix:	nhi
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the number of years that a revolving credit facility can be outstanding.

+ Details

Name:	nhi_RevolvingCreditFacilityTerm
Namespace Prefix:	nhi
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Unsecured Revolving Credit Facility

+ Details

Name:	nhi_UnsecuredRevolvingCreditFacility
Namespace Prefix:	nhi
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The net increase in interest income during the period representing the systematic and rational allocation of deferred loan origination fees less deferred loan origination costs over the term of the debt arrangement to which they pertain.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 91
-Paragraph 5, 6, 7

+ Details

Name:	us-gaap_AmortizationOfDeferredLoanOriginationFeesNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Name:	us-gaap_DebtInstrumentInterestRateAtPeriodEnd
Namespace Prefix:	us-gaap
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the required periodic payments applied to principal. (Consider the frequency of payment.)

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentsAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fixed interest rate related to the interest rate derivative.

+ Details

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of unrealized gain (loss) related to the fair value of interest rate derivatives designated as fair value hedging instruments. Recognized in earnings and offsets the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective.

+ Details

Name:	us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cost of borrowed funds accounted for as interest that was charged against earnings during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 34
-Paragraph 21

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher OTS
-Name Federal Regulation (FR)
-Number Title 12
-Chapter V
-Section 563c.102
-Paragraph 9
-Subsection II

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 9
-Article 9

+ Details

Name:	us-gaap_InterestExpense
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of loans from a bank with maturities initially due after one year or beyond the normal operating cycle if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

Name:	us-gaap_LoansPayableToBank
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from bank borrowing during the year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 18

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 19
-Subparagraph b

+ Details

Name:	us-gaap_ProceedsFromBankDebt
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration