Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

Principles of Consolidation

The consolidated financial statements include our accounts and the accounts of our majority-owned or controlled subsidiaries. The equity interests in these controlled subsidiaries not owned by us are reflected as noncontrolling interests in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in the consolidated financial statements. Investments in entities that we do not control, and variable interest entities ("VIEs") in which we are not the primary beneficiary (to the extent applicable), are not consolidated and are reflected as investments in unconsolidated joint ventures under the equity method of reporting.

Due to the fact that the Limited Partners do not have kick out rights, or substantive participating rights, the Partnership is a VIE. Because the General Partner holds majority ownership and exercises control over every aspect of the Partnership's operations, the General Partner has been determined as the primary beneficiary of the Partnership and, therefore, consolidates the Partnership.

The assets and liabilities of the General Partner and the Partnership are substantially the same, as the General Partner does not have any significant assets other than its investment in the Partnership.

Reclassifications

Certain amounts in the accompanying consolidated financial statements have been reclassified to conform to the 2019 consolidated financial statement presentation.

Real Estate Investments

Rental real property, including land, land improvements, buildings and tenant improvements, are included in real estate investments and are generally stated at cost. Construction in process and undeveloped land are included in real estate investments and are stated at cost. Real estate investments also include our equity interests in unconsolidated joint ventures that own and operate rental properties and hold land for development.

Depreciation

Buildings and land improvements are depreciated on the straight-line method over their estimated lives not to exceed 40 and 15 years, respectively, for properties that we develop, and not to exceed 30 and 10 years, respectively, for acquired properties. Tenant improvement costs are depreciated using the straight-line method over the shorter of the useful life of the asset or term of the related lease.

Cost Capitalization

Direct and certain indirect costs, including interest, clearly associated with the development, construction or expansion of real estate investments are capitalized as a cost of the property. Direct costs include all leasing commissions paid to third parties for new leases or lease renewals. We capitalize a portion of our indirect costs associated with our construction and development efforts. In assessing the amount of direct and indirect costs to be capitalized, allocations are made based on estimates of the actual amount of time spent in each activity. We do not capitalize any costs attributable to downtime or to unsuccessful projects.

Effective on January 1, 2019, only costs that are incremental to executing a lease are capitalizable. Prior to January 1, 2019, we capitalized a portion of our indirect costs associated with our leasing efforts based on the amount of time spent on leasing activities.

We capitalize interest and direct and indirect project costs associated with the initial construction of a property up to the time the property is substantially complete and ready for its intended use. In addition, we capitalize costs, including real estate taxes, insurance and utilities, that have been allocated to vacant space based on the square footage of the portion of the building not held available for immediate occupancy during the extended lease-up periods after construction of the building shell has been completed if costs are being incurred to ready the vacant space for its intended use. If costs and activities incurred to ready the vacant space cease, then cost capitalization is also discontinued until such activities are resumed. Once necessary work has been completed on a vacant space, project costs are no longer capitalized.

We cease capitalization of all project costs on extended lease-up periods when significant activities have ceased, which does not exceed the shorter of a one-year period after the completion of the building shell or when the property attains 90% occupancy.

Impairment

We evaluate our real estate assets, with the exception of those that are classified as held-for-sale, for impairment whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. If such an evaluation is considered necessary, we compare the carrying amount of that real estate asset, or asset group, with the expected undiscounted cash flows that are directly associated with, and that are expected to arise as a direct result of, the use and eventual disposition of that asset, or asset group. Our estimate of the expected future cash flows used in testing for impairment is based on, among other things, our estimates regarding future market conditions, rental rates, occupancy levels, costs of tenant improvements, leasing commissions and other tenant concessions, assumptions regarding the residual value of our properties at the end of our anticipated holding period and the length of our anticipated holding period and is, therefore, subjective by nature. These assumptions could differ materially from actual results. If our strategy changes or if market conditions otherwise dictate a reduction in

the holding period and an earlier sale date, an impairment loss could be recognized and such loss could be material. To the extent the carrying amount of a real estate asset, or asset group, exceeds the associated estimate of undiscounted cash flows, an impairment loss is recorded to reduce the carrying value of the asset to its fair value.

The determination of the fair value of real estate assets is also highly subjective, especially in markets where there is a lack of recent comparable transactions. We primarily utilize the income approach to estimate the fair value of our income producing real estate assets. We utilize marketplace participant assumptions to estimate the fair value of a real estate asset when an impairment charge is required to be measured. The estimation of future cash flows, as well as the selection of the discount rate and exit capitalization rate used in applying the income approach, are highly subjective measures in estimating fair value.

Real estate assets classified as held-for-sale are reported at the lower of their carrying value or their fair value, less estimated costs to sell. Once a property is designated as held-for-sale, no further depreciation expense is recorded.

Purchase Accounting

In January 2017, the FASB issued ASU 2017-01, Business Combinations: Clarifying the Definition of a Business. ASU 2017-01 provides guidance to determine when an acquisition meets the definition of a business or should be accounted for as an asset acquisition, resulting in more acquisitions being accounted for as asset acquisitions as opposed to business combinations. Transaction costs are capitalized for asset acquisitions while they are expensed as incurred for business combinations. ASU 2017-01 requires that when substantially all of the fair value of an acquisition is concentrated in a single identifiable asset or a group of similar identifiable assets it does not meet the definition of a business. ASU 2017-01 also revised the definition of a business to include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create an output. We early adopted ASU 2017-01 prospectively as of January 1, 2017 as permitted under the standard, which has not had a material impact to the consolidated financial statements.

As a result of adoption of ASU 2017-01, our acquisitions of properties have been accounted for as asset acquisitions as they have not met the definition of a business. Transaction costs related to asset acquisitions are capitalized. To the extent that an acquired property meets the definition of a business, we expense acquisition related costs immediately as period costs.

To the extent that we gain control of real estate properties that are accounted for as asset acquisitions, as opposed to business combinations, we accumulate the costs of pre-existing equity interest and consideration paid for additional interest acquired and we do not remeasure our pre-existing equity interest. Generally contingencies arising from an asset acquisition are only recognized when the contingency is paid or becomes payable.

We allocate the purchase price of asset acquisitions that meet the definition of a business to tangible and identified intangible assets based on their respective fair values, using all pertinent information available at the date of acquisition. Capitalized acquisition costs are also included in the total cost basis of acquired properties that are asset acquisitions. The allocation to tangible assets (buildings, tenant improvements and land) is based upon management's determination of the value of the property as if it were vacant. This “as-if vacant” value is estimated using an income, or discounted cash flow, approach that relies upon internally determined assumptions that we believe are consistent with current market conditions for similar properties. The most important assumptions in determining the allocation of the purchase price to tangible assets are the exit capitalization rate, estimated market rents and the fair value of the underlying land. The purchase price of real estate assets is also allocated to intangible assets consisting of the above or below market component of in-place leases and the value of in-place leases.

The value allocable to the above or below market component of an acquired in-place lease is determined based upon the present value (using a discount rate which reflects the risks associated with the acquired leases) of the difference between (i) the contractual amounts to be received pursuant to the lease over its remaining term and (ii) management's estimate of the amounts that would be received using fair market rates over the remaining term of the lease. The amounts allocated to above market leases are included in deferred leasing and other costs in the balance sheet and below market leases are included in other liabilities in the balance sheet; both are amortized to rental income over the remaining terms of the respective leases.

Factors considered in determining the value allocable to in-place leases include estimates, during hypothetical expected lease-up periods, of space that is actually leased at the time of acquisition, of lost rent at market rates, fixed operating costs that will be recovered from tenants and theoretical leasing commissions required to execute similar leases. These intangible assets are included in deferred leasing and other costs in the balance sheet and are amortized over the remaining term of the existing lease.

Joint Ventures

We have equity interests in unconsolidated joint ventures that primarily own and operate rental properties or hold land for development. We consolidate those joint ventures that are considered to be VIEs where we are the primary beneficiary. We analyze our investments in joint ventures to determine if the joint venture is considered a VIE and would require consolidation. We (i) evaluate the sufficiency of the total equity investment at risk, (ii) review the voting rights and decision-making authority of the equity investment holders as a group and whether there are limited partners (or similar owning entities) that lack substantive participating or kick out rights, guaranteed returns, protection against losses, or capping of residual returns within the group and (iii) establish whether activities within the venture are on behalf of an investor with disproportionately few voting rights in making this VIE determination.

To the extent that we own interests in a VIE and we (i) have the power to direct the activities that most significantly impact the economic performance of the VIE and (ii) have the obligation or rights to absorb losses or receive benefits that could potentially be significant to the VIE, then we would be determined to be the primary beneficiary and would consolidate the VIE. To the extent that we own interests in a VIE, then at each reporting period, we re-assess our conclusions as to which, if any, party within the VIE is considered the primary beneficiary. Consolidated joint ventures that are VIEs are not significant in any period presented in these consolidated financial statements.

To the extent that our joint ventures do not qualify as VIEs, they are consolidated if we control them through majority ownership interests or if we are the managing entity (general partner or managing member) and our partner does not have substantive participating rights. Control is further demonstrated by our ability to unilaterally make significant operating decisions, refinance debt and sell the assets of the joint venture without the consent of the non-managing entity and the inability of the non-managing entity to remove us from our role as the managing entity. Consolidated joint ventures that are not VIEs are not significant in any period presented in these consolidated financial statements.

We use the equity method of accounting for those joint ventures where we exercise significant influence but do not have control. Under the equity method of accounting, our investment in each joint venture is included on our balance sheet; however, the assets and liabilities of the joint ventures for which we use the equity method are not included on our balance sheet.

To the extent that we contribute assets to a joint venture, our investment in the joint venture is recorded at our cost basis in the assets that were contributed to the joint venture. To the extent that our cost basis is different than the basis reflected at the joint venture level, the basis difference is amortized over the life of the related asset and included in our share of equity in net income of the joint venture. We recognize gains on the contribution or sale of real estate to joint ventures, relating solely to the outside partner's interest, to the extent the economic substance of the transaction is a sale.

When circumstances indicate there may have been a reduction in the value of an equity investment, we evaluate whether the loss in value is other than temporary. If we conclude it is other than temporary, we recognize an impairment charge to reflect the equity investment at fair value.

There were no unconsolidated joint ventures, in which we have any recognized assets or liabilities or have retained any economic exposure to loss at December 31, 2019 that met the criteria to be considered VIEs.

Cash Equivalents

Investments with an original maturity of three months or less are classified as cash equivalents.

Valuation of Receivables

Upon the adoption of ASC 842 on January 1, 2019, our determination of the adequacy of our allowances for tenant receivables includes a binary assessment of whether or not the amounts due under a tenant’s lease agreement are probable of collection. For such amounts that are deemed probable of collection, revenue continues to be recorded on a straight-line basis over the lease term. For such amounts that are deemed not probable of collection, revenue is recorded as the lesser of (i) the amount which would be recognized on a straight-line basis or (ii) cash that has been received from the tenant, with any tenant and deferred rent receivable balances charged as a direct write-off against rental income in the period of the change in the collectability determination.

Deferred Costs

Deferred Financing Costs

Costs incurred in connection with obtaining financing are deferred and are amortized to interest expense over the term of the related loan. The costs for issuing debt, other than lines of credit, are presented on the consolidated balance sheets as a direct deduction from the debt's carrying value, while debt issuance costs related to the Partnership's unsecured line of credit are presented as assets in the consolidated balance sheets, as part of other escrow deposits and other assets.

Lease Related Costs and Acquired Lease-Related Intangible Assets

Effective on January 1, 2019, only costs that are directly incremental to executing a lease are capitalized. Prior to January 1, 2019, all direct and indirect costs, including estimated internal costs, associated with the leasing of real estate investments owned by us were capitalized and amortized over the term of the related lease.

Acquired lease-related intangible assets consist of above market lease assets and the value allocable to in-place leases. Above market lease assets are amortized as a reduction to rental income over the remaining terms of the respective leases. In-place lease intangible assets are amortized on a straight-line basis and included within depreciation and amortization in the consolidated statements of operations and comprehensive income.

Deferred leasing costs and acquired lease-related intangible assets at December 31, 2019 and 2018, excluding amounts classified as held-for-sale, were as follows (in thousands):

	2019			2018
Deferred leasing costs	$	333,706		$	307,486
Acquired lease-related intangible assets	190,595			207,057
	$	524,301		$	514,543
Accumulated amortization - deferred leasing costs	$	(109,843	)	$	(101,403	)
Accumulated amortization - acquired lease-related intangible assets	(94,014		)	(99,341		)
Total	$	320,444		$	313,799

Amounts recorded related to amortization expense for in-place leases for the years ended December 31, 2019, 2018 and 2017 totaled $22.0 million, $25.0 million and $27.2 million, respectively. Charges to rental income related to the amortization of above market lease assets for the years ended December 31, 2019, 2018 and 2017 totaled $703,000, $777,000 and $913,000, respectively.

The expected future amortization, or charge to rental income, of acquired lease-related intangible assets is summarized in the table below (in thousands):

Year	Amortization Expense		Charge to Rental Income
2020	$	18,989	$	639
2021	16,063		367
2022	13,192		353
2023	11,246		353
2024	8,690		59
Thereafter	26,630		—
	$	94,810	$	1,771

Noncontrolling Interests

Noncontrolling interests relate to the minority ownership interests in the Partnership and interests in consolidated property partnerships that are not wholly owned by the General Partner or the Partnership. Noncontrolling interests are subsequently adjusted for additional contributions, distributions to noncontrolling holders and the noncontrolling holders' proportionate share of the net earnings or losses of each respective entity. We report noncontrolling interests as a component of total equity.

When a Common Unit of the Partnership is redeemed (Note 1), the change in ownership is treated as an equity transaction by the General Partner and there is no effect on its earnings or net assets.

Revenue Recognition

On January 1, 2018, we concurrently adopted ASC 606, Revenue from Contracts with Customers ("ASC 606") and ASC 610-20, Other Income: Gains and Losses from the De-recognition of Non-financial Assets ("ASC 610-20") using a modified retrospective ("cumulative effect") method of adoption. ASC 606 has superseded nearly all existing GAAP revenue recognition guidance, although its scope excludes lease contracts, which represent our primary source of revenue. The standard’s core principle is that a company will recognize revenue when it satisfies performance obligations, by transferring promised goods or services to customers, in an amount that reflects the consideration to which the company expects to be entitled in exchange for fulfilling those performance obligations.

There was no cumulative adjustment recognized to beginning retained earnings as of January 1, 2018 as the result of adopting ASC 606 and ASC 610-20.

Rental and Related Revenue

The timing of revenue recognition under an operating lease is determined based upon ownership of the tenant improvements. If we are the owner of the tenant improvements, revenue recognition commences after the improvements are completed and the tenant takes possession or control of the space. If we determine that the tenant allowances or improvements we are funding are lease incentives, then we commence revenue recognition when possession or control of the space is turned over to the tenant. Rental income from leases is recognized on a straight-line basis.

We record lease termination fees when a tenant has executed a definitive termination agreement with us and the payment of the termination fee is not subject to any material conditions that must be met or waived before the fee is due to us.

General Contractor and Service Fee Revenue

Effective on January 1, 2018, general contractor and service fee revenues, as presented on the Consolidated Statements of Operations, are accounted for within the scope of ASC 606. General contractor and service fee revenues are comprised primarily of construction and development related revenues earned from third parties while acting in capacity of a developer, as a general contractor or a construction manager. There are other ancillary streams of revenue included in general contractor and service fee revenues (see Note 9), such as management fees earned from unconsolidated joint ventures, which are not significant.

Our construction arrangements are typically structured with only one performance obligation, which generally represents an obligation either to construct a new building or to construct fixtures in an existing building, and these single performance obligations are satisfied over time as construction progresses. We recognize revenue as we satisfy such performance obligations using the percentage of completion method, which is an input method allowed under ASC 606. Using this method, profits are recorded based on our estimates of the percentage of completion of individual contracts, commencing when the work performed under the contracts reaches a point where the final costs can be estimated with reasonable accuracy. The percentage of completion estimates are based on a comparison of the contract expenditures incurred to the estimated final costs. We believe the percentage of completion method is a faithful depiction of the transfer of goods and services as changes in job performance and estimated profitability, which result in revisions to costs and income and are recognized in the period in which the revisions are determined, have not historically been significant. We typically receive regular progress payments on the majority of our construction arrangements and such arrangements generally have an original duration of less than one year. As the result of the relatively short duration of our construction arrangements, we have elected to apply the optional disclosure exemptions, included in ASC 606, related to our remaining performance obligations for our in-process construction projects, for which any future variable consideration is not material. Changes in job performance, job conditions and estimated profitability may result in revisions to costs and income and are recognized in the period in which the revisions are determined. To the extent that a fixed-price contract is estimated to result in a loss, the loss is recorded immediately.

Opening and closing balances of construction receivables are presented separately on the Consolidated Balance Sheets. Under billed and over billed receivables on construction contracts totaled $16.5 million and $159,000, respectively, at December 31, 2019 and $29.1 million and $161,000, respectively, at December 31, 2018. Over billed receivables are included in other liabilities in the Consolidated Balance Sheets. We generally do not have any contract assets associated with our construction arrangements.

Management fees are based on a percentage of rental receipts of properties managed and are recognized as the rental receipts are collected. Maintenance fees are based upon established hourly rates and are recognized as the services are performed.

Property Sales

Only disposals representing a strategic shift in operations (for example, a disposal of a major geographic area or a major line of business) should be presented as discontinued operations in accordance with ASC 205-20, without consideration of significant continuing involvement. The Medical Office Portfolio Disposition during 2017 has met the criteria under ASC 205-20 for all of the consolidated in-service properties within the portfolio to be classified within discontinued operations (see Note 7).

Effective on January 1, 2018, gains on sales of properties, including partial sales, of non-financial assets (and in-substance non-financial assets) to non-customers are recognized in accordance with ASC 610-20, while the sale of non-financial assets with customers are governed by ASC 606. The only difference in the treatment of sales to customers and non-customers is the presentation in the Consolidated Statements of Operations (revenue and expense is reported when the sale is to a customer and net gain or loss is reported when the sale is to a non-customer). Based on the nature of our business, our property sales generally represent transactions with non-customers. In the typical course of our business, sales of non-financial assets represent only one performance

obligation and are recognized when an enforceable contract is in place, collectability is ensured and control is transferred to the buyer.

Under ASC 610-20 we are required to recognize a full gain or loss in a partial sale of non-financial assets, to the extent control is not retained. Any noncontrolling interest retained by the seller would, accordingly, be measured at fair value. We have primarily disposed of property and land in all cash transactions with no contingencies and no future involvement in the operations, and therefore, the adoption of ASC 610-20 has not significantly impacted the recognition of property and land sales.

Net Income Per Common Share or Common Unit

Basic net income per common share or Common Unit is computed by dividing net income attributable to common shareholders or common unitholders, less dividends or distributions on share-based awards expected to vest (referred to as "participating securities" and primarily composed of unvested restricted stock units), by the weighted average number of common shares or Common Units outstanding for the period.

Diluted net income per common share is computed by dividing the sum of net income attributable to common shareholders and the noncontrolling interest in earnings allocable to Limited Partner Units (to the extent the Limited Partner Units are dilutive), less dividends or distributions on participating securities that are anti-dilutive, by the sum of the weighted average number of common shares outstanding and, to the extent they are dilutive, weighted average number of Limited Partner Units outstanding and any potential dilutive securities for the period. Diluted net income per Common Unit is computed by dividing the net income attributable to common unitholders, less dividends or distributions on participating securities that are anti-dilutive, by the sum of the weighted average number of Common Units outstanding and any potential dilutive securities for the period.

The following table reconciles the components of basic and diluted net income per common share or Common Unit (in thousands): 

	2019			2018			2017
General Partner
Net income attributable to common shareholders	$	428,972		$	383,729		$	1,634,431
Less: Dividends on participating securities	(1,487		)	(1,675		)	(3,981		)
Basic net income attributable to common shareholders	427,485			382,054			1,630,450
Add back dividends on dilutive participating securities	1,487			1,675			3,981
Noncontrolling interest in earnings of common unitholders	3,678			3,528			15,176
Diluted net income attributable to common shareholders	$	432,650		$	387,257		$	1,649,607
Weighted average number of common shares outstanding	362,234			357,569			355,762
Weighted average Limited Partner Units outstanding	3,118			3,290			3,303
Other potential dilutive shares	1,987			2,438			2,946
Weighted average number of common shares and potential dilutive securities	367,339			363,297			362,011
Partnership
Net income attributable to common unitholders	$	432,650		$	387,257		$	1,649,607
Less: Distributions on participating securities	(1,487		)	(1,675		)	(3,981		)
Basic net income attributable to common unitholders	$	431,163		$	385,582		$	1,645,626
Add back distributions on dilutive participating securities	1,487			1,675			3,981
Diluted net income attributable to common unitholders	$	432,650		$	387,257		$	1,649,607
Weighted average number of Common Units outstanding	365,352			360,859			359,065
Other potential dilutive units	1,987			2,438			2,946
Weighted average number of Common Units and potential dilutive securities	367,339			363,297			362,011

There have been no participating securities that are anti-dilutive for the years ended December 31, 2019, 2018, and 2017.

Federal Income Taxes

General Partner

The General Partner has elected to be taxed as a REIT under the Code, as amended. To qualify as a REIT, the General Partner must meet a number of organizational and operational requirements, including a requirement to distribute at least 90% of its REIT taxable income to its shareholders. Management intends to continue to adhere to these requirements and to maintain the General Partner's REIT status. As a REIT, the General Partner is entitled to a tax deduction for the dividends it pays to shareholders. Accordingly, the General Partner generally will not be subject to federal income taxes as long as it currently distributes to shareholders an amount equal to or in excess of its taxable income. The General Partner is, however, generally subject to federal income taxes on any taxable income that is not currently distributed to its shareholders. If the General Partner fails to qualify as a REIT in any taxable year, it will be subject to federal income taxes and may not be able to qualify as a REIT for four subsequent taxable years.

REIT qualification reduces, but does not eliminate, the amount of state and local taxes we pay. In addition, our financial statements include the operations of taxable corporate subsidiaries that are not entitled to a dividends paid deduction and are subject to federal, state and local income taxes. As a REIT, the General Partner may also be subject to certain federal excise taxes if it engages in certain types of transactions.

The following table reconciles the General Partner's net income to taxable income before the dividends paid deduction, and subject to the 90% distribution requirement, for the years ended December 31, 2019, 2018 and 2017 (in thousands): 

	2019			2018			2017
Net income	$	432,644		$	387,268		$	1,654,341
Book/tax differences	(118,481		)	(97,079		)	(1,073,552		)
Taxable income before the dividends paid deduction	314,163			290,189			580,789
Less: capital gains	(61,531		)	(63,151		)	(441,577		)
Adjusted taxable income subject to the 90% distribution requirement	$	252,632		$	227,038		$	139,212

The General Partner's dividends paid deduction is summarized below (in thousands): 

	2019			2018			2017
Cash dividends paid	$	318,702		$	291,502		$	576,832
Cash dividends declared and paid in subsequent year that apply to current year	7,500			9,286			7,901
Cash dividends declared and paid in current year that apply to previous year	(9,286		)	(7,901		)	—
Dividends paid deduction	316,916			292,887			584,733
Less: Capital gain distributions	(61,531		)	(63,151		)	(441,577		)
Dividends paid deduction attributable to adjusted taxable income subject to the 90% distribution requirement	$	255,385		$	229,736		$	143,156

Our tax return for the year ended December 31, 2019 has not been filed. The taxability information presented for our dividends paid in 2019 is based upon management’s estimate. Consequently, the taxability of dividends is subject to change. A summary of the tax characterization of the dividends paid by the General Partner for the years ended December 31, 2019, 2018 and 2017 is as follows:

	2019		2018		2017
Common Shares
Ordinary income	80.7	%	78.4	%	23.7	%
Capital gains	19.3	%	21.6	%	76.3	%
	100.0	%	100.0	%	100.0	%

Partnership

For the Partnership, the allocated share of income and loss other than the operations of its taxable REIT subsidiary is included in the income tax returns of its partners; accordingly the only federal income taxes included in the accompanying consolidated financial statements of the Partnership are in connection with its taxable REIT subsidiary.

Deferred Tax Assets

A valuation allowance is in place for substantially all of the deferred tax assets of the taxable REIT subsidiary for all periods presented.  Based primarily on the projections of taxable income pursuant to our current operating strategy, management believes that it is more likely than not that the taxable REIT subsidiary will not generate sufficient taxable income to realize these deferred tax assets.  Income taxes are not material to our operating results or financial position. Our taxable REIT subsidiary has no significant net deferred income tax positions or unrecognized tax benefit items.

Cash Paid for Income Taxes

We paid federal, state and local income taxes, net of income tax refunds, of $7.8 million, $3.7 million and $21.0 million in 2019, 2018 and 2017, respectively.

Fair Value Measurements

We estimate fair value using available market information and valuation methodologies. Assets and liabilities recorded at fair value on the consolidated balance sheets are categorized based on the inputs to the valuation techniques as follows:

Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities to which we have access.

Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates and yield curves that are observable at commonly quoted intervals.

Level 3 inputs are unobservable inputs for the asset or liability, which are typically based on an entity's own assumptions, as there is little, if any, related market activity.

In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.

Assets or liabilities measured at fair value on a recurring basis primarily consist of derivative financial instruments (see Note 13). We were not party to any derivative financial instruments at December 31, 2019. In previous periods, we determined the fair value of derivative instruments using standard market conventions and techniques such as discounted cash flow analysis, option pricing models and termination cost at each balance sheet date. We recognized all derivatives at fair value within the line items Other Assets or Other Liabilities on our Consolidated Balance Sheet. We incorporated credit valuation adjustments to appropriately reflect nonperformance risk for us and the respective counter-party in the fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we considered the impact of netting and any applicable credit enhancements, such as mutual puts.

We determined that the majority of the inputs used to value our derivatives fell within Level 2 of the fair value hierarchy. Although the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, we assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivative positions and determined that the credit valuation adjustments were not significant to the overall valuation of our derivatives.

In addition to the acquired properties discussed in Note 4, assets measured at fair value on a non-recurring basis in the Consolidated Financial Statements consisted of real estate assets, both buildings and undeveloped land, which were determined to be impaired and recorded at fair value as discussed in Note 7. The table below aggregates the total fair value of these impaired assets as determined during the years ended December 31, 2019, 2018 and 2017, respectively, by the levels in the fair value hierarchy (in thousands):

	2019				2018				2017
	Level 1	Level 2	Level 3		Level 1	Level 2	Level 3		Level 1	Level 2	Level 3
Real estate assets	—	—	$	—	—	—	$	—	—	—	$	14,299

Derivative Financial Instruments

We periodically enter into certain interest rate protection agreements to effectively convert or cap floating rate debt to a fixed rate, and to hedge anticipated future financing transactions, both of which qualify for cash flow hedge accounting treatment. We do not utilize derivative financial instruments for trading or speculative purposes.

In August 2017, the FASB issued ASU 2017-12, Targeted improvements to accounting for hedging activities ("ASU 2017-12"). ASU 2017-12 eliminates the current requirement to separately recognize periodic hedge ineffectiveness and requires the entire effect of the hedging instrument and hedged item to be presented in the same income statement line item. ASU 2017-12 was effective for public entities on January 1, 2019 on a modified retrospective approach with early adoption permitted after the issuance. We early adopted ASU 2017-12 effective October 1, 2018 and such adoption did not have a material impact on the consolidated financial statements.

If a derivative qualifies as a cash flow hedge, the gain or loss on the derivative is recorded in accumulated other comprehensive income or loss and subsequently reclassified into interest expense in the same period during which the hedged forecasted transaction affects earnings. For all hedging relationships, we formally document the hedging relationship and its risk-management objective and strategy for undertaking the hedge, the hedging instrument, the hedged item, the nature of the risk being hedged and how the hedging instrument’s effectiveness in offsetting the hedged risk will be assessed prospectively and retrospectively.

Use of Estimates

The preparation of the financial statements requires management to make a number of estimates and assumptions that affect the reported amount of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the period. Actual results could differ from those estimates.

New Accounting Pronouncements

Recently Adopted Accounting Pronouncement

Leases

On January 1, 2019, we adopted the new lease standard, ASC 842, utilizing the available election to adopt on a prospective basis. ASC 842 has superseded all previous GAAP guidance for accounting for leases.

As part of adoption, we elected the package of practical expedients available for implementation, which included: (i) relief from re-assessing whether an expired or existing contract meets the definition of a lease, (ii) relief from re-assessing the classification of expired or existing leases at the adoption date and (iii) allowing previously capitalized initial direct leasing costs to continue to be amortized. Due in large part to electing these practical expedients, the adoption of ASC 842 did not result in recording a cumulative adjustment to the opening balance of distributions in excess of net income.

Lessor Accounting

Our primary business is the development, acquisition, and operation of industrial real estate properties that are held for investment and leased to tenants. Due to electing the package of practical expedients that allow for relief from re-assessing the classification of existing leases at the adoption date, as well as based on the characteristics of our underlying assets and leases, all of our leases are classified as operating leases. We manage residual risk through investing in properties that we believe will appreciate in value over time. We also perform a credit analysis for tenants prior to leases being executed, and on an ongoing basis, to ensure collectability is probable prior to recognizing lease revenues on an accrual basis. For lessors, the accounting under ASC 842 remains largely unchanged with the notable exception that ASC 842 requires that lessors expense certain initial direct costs, which were capitalizable under prior leasing standards, as incurred. Under the new standard, only the incremental costs of signing a lease are capitalizable. As the result of this change, we recognized $12.4 million of expense for internal costs related to successful leases for the year ended December 31, 2019, presented separately in the line item "Non-Incremental Costs Related to Successful Leases" on the Consolidated Statements of Operations and Comprehensive Income, which previously would have been capitalized. For the year ended December 31, 2018 we capitalized $12.3 million of internal lease related costs which would have been expensed had ASC 842 been effective.

ASC 842 also requires lessors to exclude certain lessor costs, such as real estate taxes and insurance, that are paid directly by lessees to third parties from rental revenue and the associated rental expense. Lessor costs that are paid by the lessor and reimbursed by the lessee continue to be recorded through rental revenue and the associated rental expense.

ASC 842 provides lessors an additional practical expedient to not separate rental recovery revenue related to lease-related services from the associated rental revenue related to the lease when certain criteria are met. The lease-related services provided to our tenants include property management, common area maintenance ("CAM") and utilities. We assessed the applicable criteria, concluding that the timing and straight-line pattern of transfer to the lessees for rental recovery revenue from our lease-related services and revenue from the underlying leases are the same and that lease classification does not change, and elected to apply this additional practical expedient.

Our leases generally include scheduled rent increases, but do not include variable payments based on indexes. Our rental revenue is primarily based on fixed, non-cancelable leases. Our variable rental revenue primarily consists of amounts recovered from lessees for property tax, insurance and CAM.

All revenues related to lease and lease-related services are included in, and comprise substantially all of, the caption "Rental and Related Revenue" on the Consolidated Statements of Operations and Comprehensive Income. The components of Rental and Related Revenue for the years ended December 31, 2019, 2018 and 2017 are as follows (in thousands and including discontinued operations):

	2019		2018		2017
Rental revenue - fixed payments	$	645,759	$	587,187	$	585,064
Rental revenue - variable payments (1)	210,074		198,249		188,635
Rental and related revenue	$	855,833	$	785,436	$	773,699

(1) Primarily includes tenant recoveries for real estate taxes, insurance and CAM.

The future minimum rents due to us under non-cancelable operating leases are as follows (in thousands):

Year	December 31, 2019
2020	$	641,578
2021	640,615
2022	577,591
2023	507,101
2024	439,324
Thereafter	1,954,723
	$	4,760,932

Lessee Accounting

ASC 842 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification determines whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use ("ROU") asset and a lease liability for all leases with a term of greater than 12 months regardless of classification.

As of December 31, 2019, our lease arrangements primarily consisted of office and ground leases. Adoption of the practical expedients resulted in the continued classification of our leases as operating leases. Expense recognized on these leases for the year ended December 31, 2019 was not material.

For these arrangements, we recognized a ROU asset and a corresponding lease liability at the January 1, 2019 adoption date of ASC 842, representing the discounted value of future lease payments required under our lease arrangements. A $40.5 million ROU asset, net of pre-existing lease related accruals, was included in Other Escrow Deposits and Other Assets, and a corresponding lease liability of $46.9 million was included in Other Liabilities on our Consolidated Balance Sheets as of December 31, 2019. In determining these amounts we elected an available practical expedient that allows us, as a lessee, to not separate lease and non-lease components.

The following table summarizes the future operating lease payments (in thousands) to be made under our non-cancellable lease arrangements:

Year	December 31, 2019		Year	December 31, 2018
2020	$	8,299	2019	$	6,487
2021	3,864		2020	7,594
2022	3,655		2021	2,987
2023	3,431		2022	2,255
2024	2,865		2023	1,949
Thereafter	84,119		Thereafter	85,523
Total undiscounted operating lease payments	$	106,233	Total undiscounted operating lease payments	$	106,795
Less: imputed interest	59,331
Present value of operating lease payments	$	46,902

The weighted average remaining lease term for our lease arrangements, on a combined basis as of December 31, 2019, was 31.4 years. The weighted average discount rate for our lease arrangements as of December 31, 2019 was 4.47%. As the discount rates implied in our lease arrangements are not readily determinable, we utilized our current credit ratings and credit yields observed from market traded securities with similar credit ratings to form a reasonable basis to establish secured borrowing rates when determining the present value of future lease payments.