Significant Accounting Policies	9 Months Ended
Sep. 30, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	SIGNIFICANT ACCOUNTING POLICIES We, the management of National Health Investors, Inc., ("NHI" or the "Company") believe that the unaudited condensed consolidated financial statements of which these notes are an integral part include all normal, recurring adjustments that are necessary to fairly present the condensed consolidated financial position, results of operations and cash flows of NHI in all material respects. The Condensed Consolidated Balance Sheet at December 31, 2014 has been derived from the audited consolidated financial statements at that date. We assume that users of these condensed consolidated financial statements have read or have access to the audited December 31, 2014 consolidated financial statements and Management's Discussion and Analysis of Financial Condition and Results of Operations and that the adequacy of additional disclosure needed for a fair presentation, except in regard to material contingencies, may be determined in that context. Accordingly, footnotes and other disclosures which would substantially duplicate those contained in our most recent Annual Report on Form 10-K for the year ended December 31, 2014 have been omitted. This condensed consolidated financial information is not necessarily indicative of the results that may be expected for a full year for a variety of reasons including, but not limited to, acquisitions and dispositions, changes in interest rates, rents and the timing of debt and equity financings. For a better understanding of NHI and its condensed consolidated financial statements, we recommend reading these condensed consolidated financial statements in conjunction with the audited consolidated financial statements for the year ended December 31, 2014, which are included in our 2014 Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission, a copy of which is available at our web site: www.nhireit.com. Principles of Consolidation - The accompanying condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, joint ventures, partnerships and consolidated variable interest entities ("VIE") where NHI controls the operating activities of the VIE, if any. All intercompany transactions and balances have been eliminated in consolidation. Net income is reduced by the portion of net income attributable to noncontrolling interests. A VIE is broadly defined as an entity with one or more of the following characteristics: (a) the total equity investment at risk is insufficient to finance the entity's activities without additional subordinated financial support; (b) as a group, the holders of the equity investment at risk lack (i) the ability to make decisions about the entity's activities through voting or similar rights, (ii) the obligation to absorb the expected losses of the entity, or (iii) the right to receive the expected residual returns of the entity; or (c) the equity investors have voting rights that are not proportional to their economic interests, and substantially all of the entity's activities either involve, or are conducted on behalf of, an investor that has disproportionately few voting rights. We apply Financial Accounting Standards Board ("FASB") guidance for our arrangements with variable interest entities ("VIEs") which requires us to identify entities for which control is achieved through means other than voting rights and to determine which business enterprise is the primary beneficiary of the VIE. In accordance with FASB guidance, management must evaluate each of the Company’s contractual relationships which creates a variable interest in other entities. If the Company has a variable interest and the entity is a VIE, then management must determine whether or not the Company is the primary beneficiary of the VIE. If it is determined that the Company is the primary beneficiary, NHI consolidates the VIE. We identify the primary beneficiary of a VIE as the enterprise that has both: (i) the power to direct the activities of the VIE that most significantly impact the entity's economic performance; and (ii) the obligation to absorb losses or the right to receive benefits of the VIE that could be significant to the entity. We perform this analysis on an ongoing basis. At September 30, 2015, we held an interest in four unconsolidated VIEs, consisting of 1) a start-up lessee in which NHI's variable interest consists of its leasehold interest, analogous to a financing arrangement, and of which we concluded that NHI was not the primary beneficiary (Note 2); 2) our joint venture in an operating company organized under provisions of the REIT Investment Diversification and Empowerment Act, (“RIDEA”) of which we concluded that NHI was not the primary beneficiary (Note 3); 3) a note receivable from, a guarantee on a letter of credit for, and a purchase option with, an unconsolidated VIE of whom we concluded that NHI was not the primary beneficiary (Note 4); and 4) two construction mortgage notes receivable aggregating $67,071,000 from an unconsolidated VIE of whom we concluded that NHI was not the primary beneficiary (Note 4). Our direct support of the above VIEs has been limited to the transactions described herein, and any decision to furnish additional direct support would be at our discretion and not obligatory. We believe our exposure to loss as a result of our involvement with these unconsolidated VIEs would be limited to our carrying value of these investments and the amount of our commitment as guarantor under the letter of credit. Generally, we lack, either directly or through related parties, any material input in the activities that most significantly impact the economic performance of these entities. We apply FASB guidance related to investments in joint ventures based on the type of controlling rights held by the members' interests in limited liability companies that may preclude consolidation by the majority equity owner in certain circumstances in which the majority equity owner would otherwise consolidate the joint venture. We structure our joint ventures to be compliant with the provisions of RIDEA, which permits NHI to receive rent payments through a triple-net lease between a property company and an operating company and is designed to give NHI the opportunity to capture additional value on the improving performance of the operating company through distributions to a taxable REIT subsidiary ("TRS"). Accordingly, the TRS holds our equity interest in an unconsolidated operating company, which we do not control, and provides an organizational structure that will allow the TRS to engage in a broad range of activities and share in revenues that would otherwise be non-qualifying income under the REIT gross income tests. Investments. - Investments in marketable debt and equity securities are categorized as trading, available-for-sale or held-to-maturity. Our investments in marketable equity securities are classified as available-for-sale securities. Unrealized gains and losses on available-for-sale securities are recorded in stockholders' equity. Our investments in marketable debt securities, consisting of U.S. government debt and long-term certificates of deposit, are classified as held-to-maturity because we have the intent and ability to hold the securities to maturity. Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity. We evaluate our securities for other-than-temporary impairments on at least a quarterly basis. Realized gains and losses from the sale of available-for-sale securities are determined on a specific-identification basis. A decline in the market value of any available-for-sale or held-to-maturity security below cost that is deemed to be other-than-temporary results in an impairment to reduce the carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established. To determine whether an impairment is other-than-temporary, we consider whether we have the ability and intent to hold the investment until a market price recovery and consider whether evidence indicating the cost of the investment is recoverable outweighs evidence to the contrary. Evidence considered in this assessment includes the reasons for the impairment, the severity and duration of the impairment, changes in value subsequent to year-end and forecasted performance of the investment. Equity-Method Investment - We report our TRS' investment in an unconsolidated entity, over whose operating and financial policies we have the ability to exercise significant influence but not control, under the equity method of accounting. Under this accounting method, our pro rata share of the entity's earnings or losses is included in our Condensed Consolidated Statements of Income. Additionally, we adjust our investment carrying amount to reflect our share of changes in an equity-method investee's capital resulting from its capital transactions. The initial carrying value of our equity-method investment is based on the fair value of the net assets of the entity at the time we acquired our interest. We estimate fair values of the net assets of our equity-method investee based on discounted cash flow models. The inputs we use in these models are based on assumptions that are within a reasonable range of current market rates for the respective investments. We evaluate our equity-method investment for impairment whenever events or changes in circumstances indicate that the carrying value of our investment may exceed the fair value. If it is determined that a decline in the fair value of our investment is not temporary, and if such reduced fair value is below its carrying value, an impairment is recorded. Determining fair value involves significant judgment. Our estimates consider all available evidence including the present value of the expected future cash flows discounted at market rates, general economic conditions and other relevant factors. Noncontrolling Interest - We present the portion of any equity that we do not own in entities that we control (and thus consolidate) as noncontrolling interest and classify such interest as a component of consolidated equity separate from total NHI stockholders' equity in our Condensed Consolidated Balance Sheets. In addition, we exclude net income attributable to the noncontrolling interest from net income attributable to common shareholders in our Condensed Consolidated Statements of Income. Use of Estimates - The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, 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. Earnings Per Share - The weighted average number of common shares outstanding during the reporting period is used to calculate basic earnings per common share. Diluted earnings per common share assume the exercise of stock options using the treasury stock method, to the extent dilutive, and also incorporate the potential dilutive impact of our 3.25% convertible senior notes due 2021. We apply the treasury stock method to our convertible debt instruments, the effect of which is that conversion will not be assumed for purposes of computing diluted earnings per share unless the average share price of our common stock for the period exceeds the conversion price per share. New Accounting Pronouncements - In February 2015 the FASB issued ASU 2015-16, Amendments to the Consolidation Analysis, under ASU 2015-02, which is generally effective for fiscal years and interim periods beginning after December 15, 2015. ASU 2015-02 changes the consolidation analysis for all reporting entities. The changes primarily affect the consolidation of limited partnerships and their equivalents (e.g., limited liability corporations), the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships, as well as structured vehicles such as collateralized debt obligations. We have yet to determine the method by which ASU 2015-02 will be adopted in 2016, and we are continuing to study the effect that our eventual adoption of this standard will have on our reported financial position and results of operations, the extent of which is not reasonably estimable at this time. In April 2015 the FASB issued ASU 2015-03, Interest-Imputation of Interest, whose primary effect is to mandate that debt issuance costs be reported in the balance sheet as a direct deduction from the face amount of the related liability. Debt issuance costs have previously been presented among assets on the balance sheet. The standard does not affect the recognition and measurement of debt issuance costs. The ASU is effective for public business entities for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. In August 2015 the FASB issued ASU 2015-15, Interest-Imputation of Interest (Subtopic 835-30) Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting. The ASU clarifies the treatment of debt issuance costs related to revolving credit facilities, upon which ASU 2015-03 was silent. ASU 2015-15 notes that the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. We believe our eventual adoption of these standards on the imputation of interest will have no material effect on our reported financial position and results of operations. In August 2015 the FASB issued ASU 2015-14, which defers the effective date of ASU 2014-09, Revenue from Contracts with Customers. ASU 2014-09 provides a principles-based approach for a broad range of revenue generating transactions, including the sale of real estate, which will generally require more estimates and more judgment and more disclosures than under current guidance. Because this ASU specifically excludes lease contracts from its scope, its application is not expected to impact our recognition of rental income on a straight-line basis. ASU 2014-09 is now effective for public entities for annual periods beginning after December 15, 2017, including interim periods therein. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. We have yet to determine the method by which ASU 2014-09 will be adopted in 2018 and we are continuing to study the effect that our eventual adoption of this standard will have on our reported financial position and results of operation, the extent of which is not reasonably estimable at this time.

SIGNIFICANT ACCOUNTING POLICIES

We, the management of National Health Investors, Inc., ("NHI" or the "Company") believe that the unaudited condensed consolidated financial statements of which these notes are an integral part include all normal, recurring adjustments that are necessary to fairly present the condensed consolidated financial position, results of operations and cash flows of NHI in all material respects. The Condensed Consolidated Balance Sheet at December 31, 2014 has been derived from the audited consolidated financial statements at that date. We assume that users of these condensed consolidated financial statements have read or have access to the audited December 31, 2014 consolidated financial statements and Management's Discussion and Analysis of Financial Condition and Results of Operations and that the adequacy of additional disclosure needed for a fair presentation, except in regard to material contingencies, may be determined in that context. Accordingly, footnotes and other disclosures which would substantially duplicate those contained in our most recent Annual Report on Form 10-K for the year ended December 31, 2014 have been omitted. This condensed consolidated financial information is not necessarily indicative of the results that may be expected for a full year for a variety of reasons including, but not limited to, acquisitions and dispositions, changes in interest rates, rents and the timing of debt and equity financings. For a better understanding of NHI and its condensed consolidated financial statements, we recommend reading these condensed consolidated financial statements in conjunction with the audited consolidated financial statements for the year ended December 31, 2014, which are included in our 2014 Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission, a copy of which is available at our web site: www.nhireit.com.

Principles of Consolidation - The accompanying condensed consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries, joint ventures, partnerships and consolidated variable interest entities ("VIE") where NHI controls the operating activities of the VIE, if any. All intercompany transactions and balances have been eliminated in consolidation. Net income is reduced by the portion of net income attributable to noncontrolling interests.

A VIE is broadly defined as an entity with one or more of the following characteristics: (a) the total equity investment at risk is insufficient to finance the entity's activities without additional subordinated financial support; (b) as a group, the holders of the equity investment at risk lack (i) the ability to make decisions about the entity's activities through voting or similar rights, (ii) the obligation to absorb the expected losses of the entity, or (iii) the right to receive the expected residual returns of the entity; or (c) the equity investors have voting rights that are not proportional to their economic interests, and substantially all of the entity's activities either involve, or are conducted on behalf of, an investor that has disproportionately few voting rights.

We apply Financial Accounting Standards Board ("FASB") guidance for our arrangements with variable interest entities ("VIEs") which requires us to identify entities for which control is achieved through means other than voting rights and to determine which business enterprise is the primary beneficiary of the VIE. In accordance with FASB guidance, management must evaluate each of the Company’s contractual relationships which creates a variable interest in other entities. If the Company has a variable interest and the entity is a VIE, then management must determine whether or not the Company is the primary beneficiary of the VIE. If it is determined that the Company is the primary beneficiary, NHI consolidates the VIE. We identify the primary beneficiary of a VIE as the enterprise that has both: (i) the power to direct the activities of the VIE that most significantly impact the entity's economic performance; and (ii) the obligation to absorb losses or the right to receive benefits of the VIE that could be significant to the entity. We perform this analysis on an ongoing basis.

At September 30, 2015, we held an interest in four unconsolidated VIEs, consisting of 1) a start-up lessee in which NHI's variable interest consists of its leasehold interest, analogous to a financing arrangement, and of which we concluded that NHI was not the primary beneficiary (Note 2); 2) our joint venture in an operating company organized under provisions of the REIT Investment Diversification and Empowerment Act, (“RIDEA”) of which we concluded that NHI was not the primary beneficiary (Note 3); 3) a note receivable from, a guarantee on a letter of credit for, and a purchase option with, an unconsolidated VIE of whom we concluded that NHI was not the primary beneficiary (Note 4); and 4) two construction mortgage notes receivable aggregating $67,071,000 from an unconsolidated VIE of whom we concluded that NHI was not the primary beneficiary (Note 4). Our direct support of the above VIEs has been limited to the transactions described herein, and any decision to furnish additional direct support would be at our discretion and not obligatory. We believe our exposure to loss as a result of our involvement with these unconsolidated VIEs would be limited to our carrying value of these investments and the amount of our commitment as guarantor under the letter of credit. Generally, we lack, either directly or through related parties, any material input in the activities that most significantly impact the economic performance of these entities.

We apply FASB guidance related to investments in joint ventures based on the type of controlling rights held by the members' interests in limited liability companies that may preclude consolidation by the majority equity owner in certain circumstances in which the majority equity owner would otherwise consolidate the joint venture.

We structure our joint ventures to be compliant with the provisions of RIDEA, which permits NHI to receive rent payments through a triple-net lease between a property company and an operating company and is designed to give NHI the opportunity to capture additional value on the improving performance of the operating company through distributions to a taxable REIT subsidiary ("TRS"). Accordingly, the TRS holds our equity interest in an unconsolidated operating company, which we do not control, and provides an organizational structure that will allow the TRS to engage in a broad range of activities and share in revenues that would otherwise be non-qualifying income under the REIT gross income tests.

Investments. - Investments in marketable debt and equity securities are categorized as trading, available-for-sale or held-to-maturity. Our investments in marketable equity securities are classified as available-for-sale securities. Unrealized gains and losses on available-for-sale securities are recorded in stockholders' equity. Our investments in marketable debt securities, consisting of U.S. government debt and long-term certificates of deposit, are classified as held-to-maturity because we have the intent and ability to hold the securities to maturity. Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity. We evaluate our securities for other-than-temporary impairments on at least a quarterly basis. Realized gains and losses from the sale of available-for-sale securities are determined on a specific-identification basis.

A decline in the market value of any available-for-sale or held-to-maturity security below cost that is deemed to be other-than-temporary results in an impairment to reduce the carrying amount to fair value. The impairment is charged to earnings and a new cost basis for the security is established. To determine whether an impairment is other-than-temporary, we consider whether we have the ability and intent to hold the investment until a market price recovery and consider whether evidence indicating the cost of the investment is recoverable outweighs evidence to the contrary. Evidence considered in this assessment includes the reasons for the impairment, the severity and duration of the impairment, changes in value subsequent to year-end and forecasted performance of the investment.

Equity-Method Investment - We report our TRS' investment in an unconsolidated entity, over whose operating and financial policies we have the ability to exercise significant influence but not control, under the equity method of accounting. Under this accounting method, our pro rata share of the entity's earnings or losses is included in our Condensed Consolidated Statements of Income. Additionally, we adjust our investment carrying amount to reflect our share of changes in an equity-method investee's capital resulting from its capital transactions.

The initial carrying value of our equity-method investment is based on the fair value of the net assets of the entity at the time we acquired our interest. We estimate fair values of the net assets of our equity-method investee based on discounted cash flow models. The inputs we use in these models are based on assumptions that are within a reasonable range of current market rates for the respective investments.

We evaluate our equity-method investment for impairment whenever events or changes in circumstances indicate that the carrying value of our investment may exceed the fair value. If it is determined that a decline in the fair value of our investment is not temporary, and if such reduced fair value is below its carrying value, an impairment is recorded. Determining fair value involves significant judgment. Our estimates consider all available evidence including the present value of the expected future cash flows discounted at market rates, general economic conditions and other relevant factors.

Noncontrolling Interest - We present the portion of any equity that we do not own in entities that we control (and thus consolidate) as noncontrolling interest and classify such interest as a component of consolidated equity separate from total NHI stockholders' equity in our Condensed Consolidated Balance Sheets. In addition, we exclude net income attributable to the noncontrolling interest from net income attributable to common shareholders in our Condensed Consolidated Statements of Income.

Use of Estimates - The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, 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.

Earnings Per Share - The weighted average number of common shares outstanding during the reporting period is used to calculate basic earnings per common share. Diluted earnings per common share assume the exercise of stock options using the treasury stock method, to the extent dilutive, and also incorporate the potential dilutive impact of our 3.25% convertible senior notes due 2021. We apply the treasury stock method to our convertible debt instruments, the effect of which is that conversion will not be assumed for purposes of computing diluted earnings per share unless the average share price of our common stock for the period exceeds the conversion price per share.

New Accounting Pronouncements - In February 2015 the FASB issued ASU 2015-16, Amendments to the Consolidation Analysis, under ASU 2015-02, which is generally effective for fiscal years and interim periods beginning after December 15, 2015. ASU 2015-02 changes the consolidation analysis for all reporting entities. The changes primarily affect the consolidation of limited partnerships and their equivalents (e.g., limited liability corporations), the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships, as well as structured vehicles such as collateralized debt obligations. We have yet to determine the method by which ASU 2015-02 will be adopted in 2016, and we are continuing to study the effect that our eventual adoption of this standard will have on our reported financial position and results of operations, the extent of which is not reasonably estimable at this time.

In April 2015 the FASB issued ASU 2015-03, Interest-Imputation of Interest, whose primary effect is to mandate that debt issuance costs be reported in the balance sheet as a direct deduction from the face amount of the related liability. Debt issuance costs have previously been presented among assets on the balance sheet. The standard does not affect the recognition and measurement of debt issuance costs. The ASU is effective for public business entities for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. In August 2015 the FASB issued ASU 2015-15, Interest-Imputation of Interest (Subtopic 835-30) Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting. The ASU clarifies the treatment of debt issuance costs related to revolving credit facilities, upon which ASU 2015-03 was silent. ASU 2015-15 notes that the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. We believe our eventual adoption of these standards on the imputation of interest will have no material effect on our reported financial position and results of operations.

In August 2015 the FASB issued ASU 2015-14, which defers the effective date of ASU 2014-09, Revenue from Contracts with Customers. ASU 2014-09 provides a principles-based approach for a broad range of revenue generating transactions, including the sale of real estate, which will generally require more estimates and more judgment and more disclosures than under current guidance. Because this ASU specifically excludes lease contracts from its scope, its application is not expected to impact our recognition of rental income on a straight-line basis. ASU 2014-09 is now effective for public entities for annual periods beginning after December 15, 2017, including interim periods therein. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. We have yet to determine the method by which ASU 2014-09 will be adopted in 2018 and we are continuing to study the effect that our eventual adoption of this standard will have on our reported financial position and results of operation, the extent of which is not reasonably estimable at this time.