Use of Estimates, Policy [Policy Text Block]

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and 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 and could cause our reported net income to vary significantly from period to period.

Revenue Recognition for Alternative Revenue Programs, Policy [Policy Text Block]

Other Revenues

As discussed in Note 3, other revenues include revenues from the provision of insurance services, management and accounting services to other long–term care providers, and rental income. Our insurance revenues consist of premiums that are generally paid in advance and then amortized into income over the policy period. We charge for management services based on a percentage of net revenues. We charge for accounting services based on a monthly fee or a fixed fee per bed of the long–term care center under contract. We record other revenues as the performance obligations are satisfied based on the terms of our contractual arrangements.

We recognize rental income based on the terms of our operating leases. Under certain of our leases, we receive variable rent, which is based on the increase in revenues of a lessee over a base year. We recognize variable rent annually or monthly, as applicable, when, based on the actual revenue of the lessee is earned.

Other Operating Expenses Policy [Policy Text Block]

Other Operating Expenses

Other operating expenses include the costs of care and services that we provide to the residents of our facilities and the costs of maintaining our facilities. Our primary patient care costs include drugs, medical supplies, purchased professional services, food, professional insurance and licensing fees. The primary facility costs include utilities and property insurance.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash and Cash Equivalents

Cash equivalents include highly liquid investments with an original maturity of three months or less when purchased.

Marketable Securities, Policy [Policy Text Block]

Investments in Marketable Securities and Restricted Marketable Securities

On January 1, 2018, the Company adopted Accounting Standards Update ("ASU") No. 2016-01 using the modified retrospective method as required in the standard. ASU No. 2016-01 revised the classification and measurement of investments in certain equity investments and required the change in fair value of many equity investments to be recognized in net income. The adoption of ASU No. 2016-01 resulted in a $68,073,000 reclassification of net unrealized gains from accumulated other comprehensive income to the opening balance sheet of retained earnings.

Our investments in marketable equity securities are carried at fair value with the changes in unrealized gains and losses recognized in our results of operations at each measurement date subsequent to January 1, 2018. Our investments in marketable debt securities are classified as available for sale securities and carried at fair value with the unrealized gains and losses recognized through accumulated other comprehensive income at each measurement date. If any adjustment to fair value on our available for sale securities reflects a significant decline in the value of the security, we consider all available evidence to evaluate the extent to which the decline is "other than temporary". Credit losses are identified when we do not expect to receive cash flows sufficient to recover the amortized cost basis of a security. In the event of a credit loss, only the amount associated with the credit loss is recognized in earnings, with the amount of loss relating to other factors recorded as a separate component of stockholders’ equity.

Financing Receivable [Policy Text Block]

Mortgage and Other Notes Receivable

In accordance with ASC Topic 310, Receivables, NHC evaluates the carrying values of its mortgage and other notes receivable on an instrument by instrument basis. On a quarterly basis, NHC reviews its notes receivable for recoverability when events or circumstances, including the non–receipt of contractual principal and interest payments, significant deteriorations of the financial condition of the borrower and significant adverse changes in general economic conditions, indicate that the carrying amount of the note receivable may not be recoverable. If necessary, impairment is measured as the amount by which the carrying amount exceeds the discounted cash flows expected to be received under the note receivable or, if foreclosure is probable, the fair value of the collateral securing the note receivable.

Lessee, Leases [Policy Text Block]

Long-Term Leases

The Company’s lease portfolio primarily consists of finance and operating real estate leases for certain skilled nursing facilities, assisted and independent living facilities, homecare offices, and pharmacy warehouses. The original terms of the leases typically range from two to fifteen years. Several of the real estate leases include renewal options which vary in length and may not include specific rent renewal amounts. We determine if an arrangement is a lease at the inception of a contract. We determine the lease term by assuming exercise of renewal options that are reasonably certain to be exercised.

On January 1, 2019 (with the adoption of ASC Topic 842, Leases, see Note 6), the Company recorded right-of-use assets and liabilities on the consolidated balance sheets for non-cancelable real estate operating leases with original or remaining lease terms in excess of one year. Leases with a lease term of 12 months or less at inception are not recorded on our consolidated balance sheets and are expensed on a straight-line basis over the lease term in our consolidated statement of operations. Finance leases remain on the consolidated balance sheets as required by previous accounting guidance.

Operating lease right-of-use assets and liabilities are recorded at the present value of the lease payments over the lease term. The present values of the lease payments are discounted using the incremental borrowing rate associated with each lease. The variable components of the lease payment that fluctuate with the operations of a healthcare facility are not included in determining the right-of-use assets and lease liabilities. Rather, these variable components are expensed as incurred.

Liability Reserve Estimate, Policy [Policy Text Block]

Accrued Risk Reserves

We are principally self–insured for risks related to employee health insurance and utilize wholly owned limited purpose insurance companies for workers’ compensation and professional liability claims. Accrued risk reserves primarily represent the accrual for risks associated with employee health insurance, workers’ compensation and professional liability claims. The accrued risk reserves include a liability for unpaid reported claims and estimates for incurred but unreported claims. Significant estimation is required in determining the reserves, particularly the assumptions of the severity of asserted claims and the quantity and severity of unknown claims. Our policy with respect to a significant portion of our workers’ compensation and professional and general liability claims is to use an actuary to assist management in estimating our exposure for claims obligation (for both asserted and unasserted claims). Our health insurance reserve is based on our known claims incurred and an estimate of incurred but unreported claims determined by our analysis of historical claims paid. We reassess our accrued risk reserves on a quarterly basis, with changes in estimated losses being recorded in the consolidated statements of operations in the period first identified.

Continuing Care Contracts and Refundable Entrance Fees, Policy [Policy Text Block]

Continuing Care Contracts and Refundable Entrance Fees

We have one continuing care retirement center (“CCRC”) within our operations. Residents at this retirement center may enter into continuing care contracts with us. The contract provides that 10% of the resident entry fee becomes non–refundable upon occupancy, and the remaining refundable portion of the entry fee is calculated using the lessor of the price at which the apartment is re–assigned or 90% of the original entry fee, plus 40% of any appreciation if the apartment exceeds the original resident’s entry fee.

Non-refundable fees are included as a component of the transaction price and are amortized into revenue over the actuarially determined remaining life of the resident, which is the expected period of occupancy by the resident. We pay the refundable portion of our entry fees to residents when they relocate from our community and the apartment is re-occupied. Refundable entrance fees are not included as part of the transaction price and are classified as non-current liabilities in the Company's consolidated balance sheets. The balances of refundable entrance fees as of December 31, 2019 and December 31, 2018 were $7,455,000 and $8,078,000, respectively.

Income Tax Uncertainties, Policy [Policy Text Block]

Other Noncurrent Liabilities

Other noncurrent liabilities include reserves primarily related to various uncertain income tax positions.

Income Tax, Policy [Policy Text Block]

Income Taxes

We utilize ASC Topic 740, Income Taxes, which requires an asset and liability approach for financial accounting and reporting for income taxes. Under this guidance, deferred tax assets and liabilities are determined based upon differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted tax laws that will be in effect when the differences are expected to reverse. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. See Note 13 for further discussion of our accounting for income taxes.

Also, under ASC Topic 740, Income Taxes, tax positions are evaluated for recognition using a more–likely–than–not threshold, and those tax positions requiring recognition are measured at the largest amount of tax benefit that is greater than 50 percent likely of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. Liabilities for income tax matters include amounts for income taxes, applicable penalties, and interest thereon and are the result of the potential alternative interpretations of tax laws and the judgmental nature of the timing of recognition of taxable income.

Share-based Payment Arrangement [Policy Text Block]

Stock–Based Compensation

Stock–based awards granted include stock options, restricted stock units, and stock purchased under our employee stock purchase plan. Stock–based compensation cost is measured at the grant date, based on the fair value of the awards, and is recognized as expense over the requisite service period only for those equity awards expected to vest.

The fair value of the restricted stock units is determined based on the stock price on the date of grant. We estimated the fair value of stock options and stock purchased under our employee stock purchase plan using the Black–Scholes model. This model utilizes the estimated fair value of common stock and requires that, at the date of grant, we use the expected term of the grant, the expected volatility of the price of our common stock, risk–free interest rates and expected dividend yield of our common stock. The fair value is amortized on a straight–line basis over the requisite service periods of the awards.

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of Credit Risks

Our credit risks primarily relate to cash and cash equivalents, restricted cash and cash equivalents, accounts receivable, marketable securities, restricted marketable securities and notes receivable. Cash and cash equivalents are primarily held in bank accounts and overnight investments. Restricted cash and cash equivalents are primarily invested in commercial paper and certificates of deposit with financial institutions and other interest-bearing accounts. Accounts receivable consist primarily of amounts due from patients (funded through Medicare, Medicaid, other contractual programs and through private payors) and from other health care companies for management, accounting and other services. We perform continual credit evaluations of our clients and maintain appropriate allowances for doubtful accounts on any accounts receivable proving uncollectible, and continually monitor and adjust these allowances as necessary. Marketable securities and restricted marketable securities are held primarily in accounts with brokerage institutions. Notes receivable relate primarily to secured loans with health care facilities as discussed in Note 11.

At any point in time we have funds in our operating accounts and restricted cash accounts that are with third party financial institutions. These balances in the U.S. may exceed the Federal Deposit Insurance Corporation (FDIC) insurance limits. While we monitor the cash balances in our operating accounts, these cash and restricted cash balances could be impacted if the underlying financial institutions fail or could be subject to other adverse conditions in the financial markets.

Our financial instruments, principally our notes receivable, are subject to the possibility of loss of the carrying values as a result of the failure of other parties to perform according to their contractual obligations. We obtain various collateral and other protective rights, and continually monitor these rights in order to reduce such possibilities of loss. We evaluate the need to provide reserves for potential losses on our financial instruments based on management's periodic review of the portfolio on an instrument by instrument basis. See Note 11 for additional information on the notes receivable.