Significant Accounting Policies (Policy)	3 Months Ended
Significant Accounting Policies (Policy)	Mar. 31, 2015
Policy Text Block [Abstract]
Consolidation, Policy	Principles of Consolidation - The accompanying consolidated financial statements include our accounts and the accounts of our wholly-owned subsidiaries and the joint venture entity over which we exercise control. All intercompany transactions and balances have been eliminated in consolidation. Net income is reduced by the portion of net income attributable to noncontrolling interests. 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. 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 consolidate investments in VIEs when we are determined to be the primary beneficiary of the VIE. We may change our assessment of a VIE due to events such as modifications of contractual arrangements that affect the characteristics or adequacy of the entity's equity investments at risk and the disposal of all or a portion of an interest held by the primary beneficiary. 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 March 31, 2015, we held an interest in one unconsolidated VIE, of which we were not the primary beneficiary. We also 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 the REIT Investment Diversification and Empowerment Act of 2007 ("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. 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 method of accounting, 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, Policy	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, Policy	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. Diluted earnings per share 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 for the period exceeds the conversion price per share.
New Accounting Pronouncements, Policy	New Accounting Pronouncements - In February 2015, the FASB issued 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 cannot be 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. We have yet to determine the method by which ASU 2015-03 will be adopted. We believe our eventual adoption of this standard will have no material effect on our reported financial position and results of operations.

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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- Definition

Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.

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