This item represents the number of shares held as an investment which were given up in an exchange during the period.

Name:	nhi_CommonSharesGivenUpInExchange
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- Definition

This item represents the number of shares held as an investment which were received in an exchange during the period.

+ Details

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- Definition

This item represents the number of shares held as an investment which were sold during the period.

+ Details

Name:	nhi_CommonSharesSold
Namespace Prefix:	nhi
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of preferred shares held as an investment which were sold during the period

+ Details

Name:	nhi_PreferredSharesSold
Namespace Prefix:	nhi
Data Type:	xbrli:sharesItemType
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Period Type:	duration

- Definition

This item represents the gross unrealized gains for securities which are categorized neither as held-to-maturity nor trading securities. Such gross unrealized gains are the excess of the fair value of the Available-for-sale Securities over their carrying value as of the reporting date. Such gross unrealized gains are included in other comprehensive income in the statement of shareholders' equity, unless the Available-for-sale Security is designated as a hedge. All or a portion of the unrealized holding gain of an available-for-sale security that is designated as being hedged in a fair value hedge shall be recognized in earnings during the period of the hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13, 19

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Interest and dividend income on all securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 2, 3

-Article 9

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments of the subject investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

+ Details

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Investments In Marketable Securities (Narrative) (Details) (USD $) In Thousands, except Share data	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Dividend and interest income from marketable securities			$ 674	$ 941
Net realized gains on sales of marketable securities	1,090	2	9,899	2
Available-for-sale Securities, Gross Unrealized Gains			5,327		15,330
National Healthcare Corp [Member]
Preferred Shares Sold			96,330
LTC Properties Inc [Member]
Common Shares Sold			381,000
National Healthcare and LTC Properties Inc [Member]
Net realized gains on sales of marketable securities			8,809
Nationwide Health Properties [Member]
Common Shares Given Up In Exchange	50,000
Net realized gains on sales of marketable securities	$ 1,090
Ventas Inc [Member]
Common Shares Received In Exchange	39,330