Principles of Consolidation. Our consolidated financial statements include our accounts and the accounts of other subsidiaries and joint ventures (including partnerships and limited liability companies) over which we have control. All intercompany transactions, balances, and profits have been eliminated in consolidation. Investments acquired or created are evaluated based on the accounting guidance relating to variable interest entities (“VIEs”), which requires the consolidation of VIEs in which we are considered to be the primary beneficiary. If the investment is determined not to be a VIE, then the investment is evaluated for consolidation primarily using a voting interest model. In determining if we have a controlling financial interest, we consider factors such as ownership interests, authority to make decisions, kick-out rights and participating rights. As of December 31, 2019, two of our consolidated operating partnerships are VIEs. We are considered the primary beneficiary of both consolidated operating partnerships and therefore consolidate these operating partnerships. As of December 31, 2019, we held approximately 92% and 95% of the outstanding common limited partnership units and the sole 1% general partnership interest in each of these consolidated operating partnerships.

Acquisitions of Real Estate. Upon the acquisition of real estate, we determine the fair value of tangible and intangible assets, which includes land, buildings (as-if-vacant), furniture and fixtures, the value of in-place leases, including above and below market leases, and acquired liabilities. In estimating these values, we apply methods similar to those used by independent appraisers of income-producing property. Estimates of fair value of acquired debt are based upon interest rates available for the issuance of debt with similar terms and remaining maturities. Depreciation is computed on a straight-line basis over the remaining useful lives of the related tangible assets. The value of in-place leases and above or below market leases is amortized over the estimated average remaining life of leases in place at the time of acquisition; the net carrying value of in-place leases are included in other assets, net and the net carrying value of above or below market leases are included in other liabilities, net in our consolidated balance sheets.

During the years ended December 31, 2019, 2018, and 2017, we recognized amortization expense of approximately $10.4 million, $9.4 million, and $1.3 million, respectively, related to in-place leases. The net amortization of above-market and below-market leases increased rental revenues by $0.1 million and $0.2 million during the years ended December 31, 2019 and 2018, respectively. We did not recognize any net amortization of above-market and below-market leases during the year ended December 31, 2017. During the year ended December 31, 2019, the weighted average amortization periods for both in-place and net above and below market leases were approximately six months. During the year ended December 31, 2018, the weighted average amortization period for in-place and net above and below market leases were approximately seven months and five months. During the year ended December 31, 2017, the weighted average amortization period for in-place leases was approximately six months.

Asset Impairment. Long-lived assets are reviewed for impairment annually or whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. Impairment may exist if estimated future undiscounted cash flows associated with long-lived assets are not sufficient to recover the carrying value of such assets. We consider projected future undiscounted cash flows, trends, strategic decisions regarding future development plans, and other factors in our assessment of whether impairment conditions exist. While we believe our estimates of future cash flows are reasonable, different assumptions regarding a number of factors, including market rents, economic conditions, and occupancies, could significantly affect these estimates. When impairment exists, the long-lived asset is adjusted to its fair value. In estimating fair value, management uses appraisals, management estimates, and discounted cash flow calculations which utilize inputs from a marketplace participant’s perspective. In addition, we evaluate our equity investments in joint ventures and if we believe there is an other than temporary decline in market value of our investment below our carrying value, we will record an impairment charge. We did not record any impairment charges for the years ended December 31, 2019, 2018, or 2017.

The value of our properties under development depends on market conditions, including estimates of the project start date as well as estimates of demand for multifamily communities. We have reviewed market trends and other marketplace information and have incorporated this information as well as our current outlook into the assumptions we use in our impairment analyses.

We believe the carrying value of our operating real estate assets, properties under development, and land is currently recoverable. However, if market conditions deteriorate or if changes in our development strategy significantly affect any key assumptions used in our fair value estimates, we may need to take material charges in future periods for impairments related to existing assets. Any such non-cash charges could have an adverse effect on our consolidated financial position and results of operations.

Cash and Cash Equivalents. All cash and investments in money market accounts and other highly liquid securities with a maturity of three months or less at the date of purchase are considered to be cash and cash equivalents. We maintain the majority of our cash and cash equivalents at major financial institutions in the United States and deposits with these financial institutions may exceed the amount of insurance provided on such deposits; however, we regularly monitor the financial stability of these financial institutions and believe we are not currently exposed to any significant default risk with respect to these deposits.

Cost Capitalization. Real estate assets are carried at cost plus capitalized carrying charges. Carrying charges are primarily interest and real estate taxes which are capitalized as part of properties under development. Capitalized interest is generally based on the weighted average interest rate of our unsecured debt. Expenditures directly related to the development and improvement of real estate assets are capitalized at cost as land and buildings and improvements. Indirect development costs, including salaries and benefits and other related costs directly attributable to the development of properties, are also capitalized. We begin capitalizing development, construction, and carrying costs when the development of the future real estate asset is probable and activities necessary to prepare the underlying real estate for its intended use have been initiated. All construction and certain carrying costs are capitalized and reported in the balance sheet as properties under development until the apartment homes are substantially completed. As apartment homes within development properties are completed, the total capitalized development cost of each apartment home is transferred from properties under development including land to buildings and improvements.

As discussed above, carrying charges are principally interest and real estate taxes capitalized as part of properties under development. Capitalized interest was approximately $14.1 million, $13.6 million, and $15.2 million for the years ended December 31, 2019, 2018, and 2017, respectively. Capitalized real estate taxes were approximately $2.8 million, $2.2 million, and $2.4 million for the years ended December 31, 2019, 2018, and 2017, respectively.

Where possible, we stage our construction to allow leasing and occupancy during the construction period, which we believe minimizes the duration of the lease-up period following completion of construction. Our accounting policy related to properties in the development and leasing phase is to expense all operating costs associated with completed apartment homes. We capitalize renovation and improvement costs we believe extend the economic lives of depreciable property. Capital expenditures subsequent to initial construction are capitalized and depreciated over their estimated useful lives.

Derivative Financial Instruments. Derivative financial instruments are recorded in the consolidated balance sheets at fair value and presented on a gross basis for financial reporting purposes even when those instruments are subject to master netting arrangements and may otherwise qualify for net presentation. Accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether we have elected to designate a derivative in a hedging relationship and apply hedge accounting, and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows or other types of forecasted transactions are cash flow hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes attributable to the earnings effect of the hedged transactions. We may enter into derivative contracts which are intended to economically hedge certain of our risks, for which hedge accounting does not apply or we elect not to apply hedge accounting.

equity investment. The results of operations for properties sold during the period or classified as held for sale at the end of the period, and meeting the above criteria of discontinued operations, are classified as discontinued operations for all periods presented. Real estate assets held for sale are measured at the lower of carrying amount or fair value less costs to sell and are presented separately in the accompanying consolidated balance sheets. Subsequent to classification of a property as held for sale, no further depreciation is recorded. Consolidated operating properties sold or classified as held for sale, which do not meet the above criteria of discontinued operations are not included in discontinued operations and the related gains and losses are included in continuing operations. Properties sold by our unconsolidated entities which do not meet the above criteria of discontinued operations are not included in discontinued operations and related gains or losses are reported as a component of equity in income of joint ventures.

Gains on sale of real estate are recognized when the criteria for derecognition of an asset is met, including when a contract exists and the buyer obtained control of the nonfinancial asset sold, in accordance with accounting principles generally accepted in the United States of America ("GAAP"). As a result, most of our future contributions of nonfinancial assets to our joint ventures, if any, will result in the recognition of a full gain or loss as if we sold 100% of the nonfinancial asset.

Fair Value. For financial assets and liabilities recorded at fair value on a recurring or non-recurring basis, fair value is the price we would receive to sell an asset, or pay to transfer a liability, in an orderly transaction with a market participant at the measurement date. In the absence of such data, fair value is estimated using internal information consistent with what market participants would use in a hypothetical transaction.

Deferred Compensation Plan Investments. The estimated fair values of investment securities classified as deferred compensation plan investments are based on quoted market prices utilizing public information for the same transactions. Our deferred compensation plan investments are recorded in other assets in our consolidated balance sheets. The inputs associated with the valuation of our recurring deferred compensation plan investments are included in Level 1 of the fair value hierarchy.

Derivative Financial Instruments. The estimated fair values of derivative financial instruments are valued using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and volatility. The fair values of interest rate swaps and caps are estimated using the market-standard methodology of netting the discounted fixed cash payments and the discounted expected variable cash receipts. The variable cash receipts are based on an expectation of interest rates (forward curves) derived from observable market interest rate curves. In addition, credit valuation adjustments, which consider the impact of any credit enhancements to the contracts, are incorporated in the fair values to account for potential nonperformance risk, including our own nonperformance risk and the respective counterparty’s nonperformance risk. The fair value of interest rate caps is determined using the market-standard methodology of discounting the future expected cash receipts which would occur if variable interest rates rise above the strike rate of the caps. The variable interest rates used in the calculation of projected receipts on the cap are based on an expectation of future interest rates derived from observed market interest rate curves and volatilities.

Although we have determined the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, such as estimates of current credit spreads, to evaluate the likelihood of default. However, we have assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivative positions and have determined the credit valuation adjustments are not significant to the overall valuation of our derivatives. As a result, we have determined our derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy.

Non-recurring Fair Value Measurements. Certain assets are measured at fair value on a non-recurring basis. These assets are not measured at fair value on an ongoing basis, but are subject to fair value adjustments in certain circumstances. Long-lived assets such as the land, real estate asset, and in-place leases acquired with an operating property are measured in the form of cash received unless otherwise noted. These assets are recorded at fair value if they are impaired using the fair value methodologies

used to measure long-lived assets described above at "Asset Impairment." The inputs associated with the valuation of long-lived assets are generally included in Level 3 of the fair value hierarchy, unless a quoted price for a similar long-lived asset in an active market exists, at which time they are included in Level 2 of the fair value hierarchy.

Financial Instrument Fair Value Disclosures. As of December 31, 2019 and 2018, the carrying values of cash and cash equivalents, accounts receivable, accounts payable, accrued expenses, and distributions payable represent fair value because of the short-term nature of these instruments. The carrying value of restricted cash approximates its fair value based on the nature of our assessment of the ability to recover these amounts. The carrying value of our notes receivable, which are included in other assets, net in our consolidated balance sheets, approximates their fair value. The estimated fair values are based on certain factors, such as market interest rates, terms of the note, and credit worthiness of the borrower. These financial instruments utilize Level 3 inputs. In calculating the fair value of our notes payable, interest rate, and spread assumptions reflect current credit worthiness and market conditions available for the issuance of notes payable with similar terms and remaining maturities. These financial instruments utilize Level 2 inputs.

Income Recognition. On January 1, 2019, we adopted Accounting Standards Update ("ASU") 2016-02, "Leases" which is codified as ASC 842, Leases. The majority of our revenues are derived from real estate lease contracts which are accounted for pursuant to ASC 842 and presented as property revenues, which include rental revenue and revenue from amounts received under contractual terms for other services provided to our customers. Our other revenue streams include fee and asset management income in accordance with other revenue guidance, ASC 606, Revenues from Contracts with Customers. A detail of these revenue streams are discussed below:

Property Revenue: We earn rental revenue from operating lease contracts for the use of dedicated spaces within owned assets which is recognized on a straight-line basis over the applicable lease term, net of amounts related to lease contracts identified as uncollectible. We also earn revenues from amounts received under contractual terms for other services considered non-lease components within a lease contract, primarily consisting of utility rebillings and other transactional fees, and are charged to our residents and recognized monthly as earned. We elected the practical expedient under ASU 2016-02 to not separate lease and non-lease components and have presented our property revenues combined based upon the lease being determined to be the predominant component. Any uncollectible amounts related to individual lease contracts are presented as an adjustment to property revenue. Any renewal options of real estate lease contracts are considered a new, separate contract and will be recognized at the time the option is exercised on a straight-line basis over the renewal period.

Fee and Asset Management Income: We receive property management, asset management, and development and construction fees from our joint ventures for managing the ventures and managing the activities, development, and construction of their operating communities. While the individual activities related to these fees may vary, the services provided are substantially similar, have the same pattern of transfer, and are considered to be individual performance obligations composed of a series of distinct services recognized monthly as earned.

We also earn construction fees for construction management and general contracting services we provide to third-party owners of multifamily and commercial properties. These fees are recognized as we satisfy our single performance obligation over time based on a percentage-of-completion of cost basis which we believe is an accurate depiction of the transfer of control to our customers. For these contracts, significant judgment is used to estimate the cost plus margin for the project fee and our profitability on those contracts is dependent on the ability to accurately predict such factors. We record third-party construction receivables for amounts where we have unconditional rights to payment but have not received and liabilities for amounts incurred but not paid. For the years ended December 31, 2019 and 2018, these contract receivable and liability balances were immaterial.

Reclassifications. Certain amounts have been presented separately within financing activities in the consolidated statements of cash flows for the years ended December 31, 2018 and 2017 to conform to the current-year presentation. These changes in presentation had no impact in consolidated cash flows from financing activities. Upon our adoption of ASU 2016-02 on January 1, 2019 we were required, based on our election of a practical expedient, to combine lessor lease and non-lease components as a single component under certain conditions. For the years ended December 31, 2018 and 2017, we combined other property revenues of $112.5 million and $130.4 million, respectively, with rental revenues of $842.0 million and $770.5 million, respectively, to conform to the current year presentation.

Insurance. Our primary lines of insurance coverage are property, general liability, health, workers’ compensation, and cyber security. We believe our insurance coverage adequately insures our properties against the risk of loss attributable to fire, earthquake, hurricane, tornado, flood, and other perils and adequately insures us against other risks. Losses are accrued based upon our estimates of the aggregate liability for claims incurred using certain actuarial assumptions followed in the insurance industry and based on our experience.

Other Assets, Net. Other assets in our consolidated financial statements include investments under deferred compensation plans, deferred financing costs, non-real estate leasehold improvements and equipment, notes receivable, operating lease right-of-use assets, prepaid expenses, and other miscellaneous receivables. Investments under deferred compensation plans are classified as trading securities and are adjusted to fair market value at period end. For a further discussion of our investments under deferred compensation plans, see Note 11, “Share-based Compensation and Benefit Plans.” Deferred financing costs are related to our unsecured credit facility, and are amortized no longer than the terms of the related facility on the straight-line method, which approximates the effective interest method. Corporate leasehold improvements and equipment includes expenditures related to renovation and construction of office space we lease. These leasehold improvements are depreciated using the straight-line method over the shorter of the expected useful lives or the lease terms which generally range from three to ten years.

Notes Receivable. We have one note receivable included in Other assets, net in our consolidated balance sheets, relating to a real estate secured loan to an unaffiliated third party. During 2019, we received payments of approximately $1.4 million in principal and approximately $0.6 million in interest on this note which matures on October 1, 2025. At December 31, 2019 and 2018, the outstanding note receivable balance was approximately $7.9 million and $9.3 million, respectively, and the weighted average interest rate was approximately 7.0% and 4.0%, respectively. Interest is recognized over the life of the note and is included in interest and other income in our consolidated statements of income and comprehensive income. We consider a note receivable to be impaired if it is probable we will not collect all contractually due principal and interest. We do not accrue interest when a note is considered impaired and an allowance is recorded for any principal and previously accrued interest which is not believed to be collectible. All cash receipts on impaired notes are applied to reduce the principal amount of such notes until the principal has been recovered and, thereafter, are recognized as interest income. There were no impairments as of December 31, 2019 or 2018.

Reportable Segments. We operate in a single reportable segment which includes the ownership, management, development, redevelopment, acquisition, and construction of multifamily apartment communities. Each of our operating properties is considered a separate operating segment as each property earns revenues and incurs expenses, individual operating results are reviewed and discrete financial information is available. We do not distinguish or group our consolidated operations based on geography, size or type. Our multifamily apartment communities have similar long-term economic characteristics and provide similar products and services to our residents. Further, all material operations are within the United States and no multifamily apartment community comprises more than 10% of consolidated revenues. As a result, our operating properties are aggregated into a single reportable segment. Our multifamily communities generate property revenue through the leasing of apartment homes, which comprised approximately 99% of our total property revenues and total non-property income, excluding income (loss) on deferred compensation plans, for each of the years ended December 31, 2019, 2018, and 2017.

Restricted Cash. Restricted cash consists of escrow deposits held by lenders for property taxes, insurance and replacement reserves, cash required to be segregated for the repayment of residents’ security deposits, and escrowed amounts related to our development and acquisition activities. Substantially all restricted cash is invested in demand and short-term instruments.

Share-based Compensation. Compensation expense associated with share-based awards is recognized in our consolidated statements of income and comprehensive income using the grant-date fair values. Compensation cost for all share-based awards, including options, requires measurement at estimated fair value on the grant date and recognition of compensation expense over the requisite service period for awards expected to vest. The fair value of stock option grants is estimated using the Black-Scholes valuation model. Valuation models require the input of assumptions, including judgments to estimate the expected stock price volatility, expected life, and forfeiture rate. The compensation cost for share-based awards is based on the market value of the shares on the date of grant and is adjusted as actual forfeitures occur.

and related disclosures. Our more significant estimates include estimates supporting our impairment analysis related to the carrying values of our real estate assets. These estimates are based on historical experience and other assumptions believed to be reasonable under the circumstances. Future events rarely develop exactly as forecasted, and the best estimates routinely require adjustment.

Recent Accounting Pronouncements. In August 2018, the Financial Accounting Standards Board ("FASB") issued ASU 2018-15, "Intangibles—Goodwill and Other— Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract." ASU 2018-15 aligns the accounting for costs incurred to implement a cloud computing arrangement which is a service arrangement with the guidance on capitalizing costs associated with developing or obtaining internal-use software. ASU 2018-15 is effective for interim and annual periods beginning after December 15, 2019, and early adoption is permitted. This standard may be applied using the prospective transition method which is applicable to costs for activities on service contracts entered, renewed, materially modified, or performed after the effective date or the retrospective transition method which allows us to recognize a cumulative effect adjustment to the opening balance of retained earnings, if any, as of the adoption date. We adopted as of January 1, 2020, using the prospective transition method and will present future qualified capitalizable costs relating to new completed cloud computing arrangements which are service arrangements as prepaid assets within other assets on our consolidated balance sheets, as cash flows from operating activities on our consolidated statement of cash flows, and the associated amortization as general and administrative expenses on our consolidated statements of income and comprehensive income. Our adoption of ASU 2018-15 will not have a material impact on our consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, "Leases." ASU 2016-02 and its related amendments codify ASC 842 and provides new guidance for accounting for leases. We adopted ASC 842 as of January 1, 2019 using the transition method which allows us to recognize a cumulative-effect adjustment to the opening balance of retained earnings as of the adoption date and to initially apply the new lease standard to leases which existed as of January 1, 2019. Upon our adoption of ASC 842, as a lessee we recorded a right-of-use asset and a corresponding liability in our consolidated balance sheet, as a lessor we now present combined lease and non-lease components as a single component in our consolidated statement of income and comprehensive income, and this ASU did not have an impact on the opening balance of retained earnings as of the adoption date. In addition to the transition practical expedient, we elected other practical expedients during our adoption of the new lease standard. For both lessor and lessee contracts, we elected the practical expedient package to not reassess: (i) whether any expired or existing contract was a lease or contained a lease, (ii) the lease classification of any expired or existing leases, and (iii) the accounting for initial direct costs for any existing leases.

We earn income from the leasing of our owned real estate properties which is considered our only lessor underlying asset class. Substantially all of our real estate lessor commitments will continue to be accounted for as operating leases and the new leasing standard did not have a material impact on our property revenues. As a lessee, we enter into lease contracts to facilitate the operations and needs of our business and our operating leases primarily consist of our office facility leases which are considered our only lessee underlying asset class. Our lessee operating lease commitments are subject to this standard and recognized as operating lease liabilities and right-of-use assets upon adoption. See above "Income Recognition," as it relates to our lessor leases and Note 14, "Commitments and Contingencies" as it relates to our lessee leases for additional disclosures required by ASC 842.