On February 26, 2014, we commenced a best efforts initial public offering, or our initial offering, in which we offered to the public up to $1,900,000,000 in shares of our common stock. As of April 22, 2015, the deregistration date of our initial public offering, or our initial offering, we had received and accepted subscriptions in our initial offering for 184,930,598 shares of our common stock, or $1,842,618,000, excluding shares of our common stock issued pursuant to our initial distribution reinvestment plan, or the Initial DRIP. As of April 22, 2015, a total of $18,511,000 in distributions were reinvested that resulted in 1,948,563 shares of our common stock being issued pursuant to the DRIP portion of our initial offering.Initial DRIP.

On March 25, 2015, we filed a Registration Statement on Form S-3 under the Securities Act of 1933, as amended, or the Securities Act, to register a maximum of $250,000,000 of additional shares of our common stock to be issued pursuant to our distribution reinvestment plan,the Initial DRIP, or the Secondary2015 DRIP Offering. The Registration Statement on Form S-3 was automatically effective with the United States Securities and Exchange Commission, or SEC, upon its filing; however, we did not commenceWe commenced offering shares pursuant to the Secondary2015 DRIP Offering until April 22, 2015, following the deregistration of our initial offering. Effective October 5, 2016, we amended and restated the Initial DRIP, or the Amended and Restated DRIP, to amend the price at which shares of our common stock are issued pursuant to the Secondary2015 DRIP Offering. See Note 13, Equity — Distribution Reinvestment Plan, for a further discussion. As of September 30, 2017, a total of $155,616,000 in distributions were reinvested and 16,712,987We continued to offer shares of our common stock pursuant to the 2015 DRIP Offering until the termination and deregistration of such offering on March 29, 2019. As of March 29, 2019, a total of $245,396,000 in distributions were reinvested that resulted in 26,386,545 shares of common stock being issued pursuant to the Secondary2015 DRIP Offering.

Our accompanying condensed consolidated financial statements have been prepared by us in accordance with GAAP in conjunction with the rules and regulations of the United States Securities and Exchange Commission, or SEC. Certain information and footnote disclosures required for annual financial statements have been condensed or excluded pursuant to SEC rules and regulations. Accordingly, our accompanying condensed consolidated financial statements do not include all of the information and footnotes required by GAAP for complete financial statements. Our accompanying condensed consolidated financial statements reflect all adjustments which are, in our view, of a normal recurring nature and necessary for a fair presentation of our financial position, results of operations and cash flows for the interim period. Interim results of operations are not necessarily indicative of the results to be expected for the full year; such full year results may be less favorable.

Resident receivables are carried net of an allowance for uncollectible amounts.credit losses. An allowance is maintained for estimated losses resulting from the inability of certain tenants or residents and payors to meet the contractual obligations under their lease or service agreements. We also maintain an allowance for deferred rent receivables arising from the straight-line recognitionSubstantially all of rents. Suchsuch allowances are chargedrecorded as direct reductions of resident fees and services revenue as contractual adjustments provided to bad debt expense, which is included in general and administrativethird-party payors or implicit price concessions in our accompanying condensed consolidated statements of operations and comprehensive income (loss). Our determination of the adequacy of these allowances is based primarily upon evaluations of historical loss experience, the tenant’s or resident’sresidents’ financial condition, security deposits, letters of credit, lease guarantees,cash collection patterns by payor and by state, current economic conditions, future expectations in estimating credit losses and other relevant factors.

As of September 30, 2017March 31, 2020 and December 31, 2016,2019, we had $10,568,000$10,809,000 and $9,597,000,$11,435,000, respectively, in allowance for uncollectible accounts,allowances, which waswere determined necessary to reduce receivables toby our estimate of the amount recoverable. For the three and nine months ended September 30, 2017, $0 and $9,000, respectively, of our receivables were directly written off to bad debt expense. For the three and nine months ended September 30, 2016, we did not write off any receivables to bad debt expense.expected future credit losses. For the three months ended September 30, 2017March 31, 2020 and 2016, $1,455,0002019, we increased allowances by $3,826,000 and $1,467,000,$3,244,000, respectively, and reduced allowances for collections or adjustments by $2,478,000 and $1,227,000, respectively. For the three months ended March 31, 2020 and 2019, $1,974,000 and $1,243,000, respectively, of our receivables were written off against the allowancerelated allowances.

We periodically evaluate our long-lived assets, primarily consisting of investments in real estate that we carry at our historical cost less accumulated depreciation, for uncollectible accounts,impairment when events or changes in circumstances indicate that its carrying value may not be recoverable. Indicators we consider important and forthat we believe could trigger an impairment review include, among others, the nine months ended September 30, 2017following:

As of September 30, 2017 and December 31, 2016, we did not have any allowance for uncollectible accounts for deferred rent receivables. For the three months ended September 30, 2017March 31, 2020, we determined that one skilled nursing facility was impaired, and 2016, $145,000as such, we recognized an impairment charge of $3,711,000 to reduce the carrying value of such asset to $3,840,000. The fair value of such property was based on its projected sales price obtained from an independent third party using comparable market information, which was considered a Level 2 measurement within the fair value hierarchy. No impairment charges on long-lived assets were recognized for the three months ended March 31, 2019.

A property or a group of properties is required to be reported in discontinued operations in the statements of operations and $0, respectively,comprehensive income (loss) for current and prior periods if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results when either: (i) the component has been disposed of our deferred rent receivables were directly written offor (ii) is

We classify our marketable debt security investment as held-to-maturity because we have the positive intent and $28,000, respectively,ability to hold the security to maturity, and we have not recorded any unrealized holding gains or losses on such investment. Our held-to-maturity security is recorded at amortized cost and adjusted for the amortization of premiums or discounts through maturity. Prior to the adoption of ASC Topic 326, a loss was recognized in earnings when we determined declines in the fair value of marketable securities were other-than-temporary. For the three months ended March 31, 2019, we did not incur any such losses. Effective January 1, 2020, we evaluated our deferred rent receivables were directly written off to bad debt expense.

As of September 30, 2017March 31, 2020 and December 31, 2016,2019, accounts payable and accrued liabilities primarily includes insurance payable of $26,827,000 and $19,136,000, respectively, reimbursement of payroll related costs to the managers of our senior housing — RIDEA facilities and integrated senior health campuses of $23,195,000$33,472,000 and $20,992,000,$24,118,000, respectively, accrued property taxesinsurance reserves of $15,152,000$33,237,000 and $12,766,000,$35,581,000, respectively, accrued distributions of $9,830,000 and $10,009,000, respectively, and accrued capital expenditures to unaffiliated third parties of $6,142,000$22,398,000 and $5,066,000,$25,019,000, respectively, accrued property taxes of $15,885,000 and $14,501,000, respectively, and accrued distributions of $9,955,000 and $9,974,000, respectively.

On October 15, 2015, we acquired a commercial mortgage-backed debt security, or debt security, from an unaffiliated third party. The following table showsdebt security bears an interest rate on the changesstated principal amount thereof equal to 4.24% per annum, the terms of which security provide for monthly interest-only payments. The debt security matures on August 25, 2025 at a stated amount of $93,433,000, resulting in an anticipated yield-to-maturity of 10.0% per annum. The debt security was issued by an unaffiliated mortgage trust and represents a 10.0% beneficial ownership interest in such mortgage trust. The debt security is subordinate to all other interests in the mortgage trust and is not guaranteed by a government-sponsored entity.