Summary of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2017

Earnings Per Share, Basic and Diluted [Line Items]

ORGANIZATION

Liberty Property Trust (the “Trust”) is a self-administered and self-managed Maryland real estate investment trust (a “REIT”). Substantially all of the Trust’s assets are owned directly or indirectly, and substantially all of the Trust’s operations are conducted directly or indirectly, by its subsidiary, Liberty Property Limited Partnership, a Pennsylvania limited partnership (the “Operating Partnership” and, together with the Trust and their consolidated subsidiaries, the “Company”). The Trust is the sole general partner and also a limited partner of the Operating Partnership, owning 97.7% of the common equity of the Operating Partnership at December 31, 2017. The Company owns and operates industrial properties nationally and owns and operates office properties in a focused group of office markets. Additionally, the Company owns certain assets in the United Kingdom. Unless otherwise indicated, the notes to the Consolidated Financial Statements apply to both the Trust and the Operating Partnership. The terms the "Company,” “we,” “our” and “us” means the Trust and Operating Partnership collectively.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("US GAAP") requires management to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes.

Actual results could differ from those estimates.

Principles of Consolidation

The consolidated financial statements of the Company include the Trust, the Operating Partnership, wholly owned subsidiaries and those subsidiaries in which the Company owns a majority voting interest with the ability to control operations of the subsidiaries and where no approval, veto or other important rights have been granted to the noncontrolling shareholders. The Company consolidates joint ventures that are considered to be variable interest entities (“VIEs”) where we are the primary beneficiary. The Company (i) evaluates the sufficiency of the total equity investment at risk, (ii) reviews the voting rights and decision-making authority of the equity investment holders as a group and whether there are any guaranteed returns, protection against losses, or capping of residual returns within the group and (iii) establishes 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 the Company (i) is the sole entity that has the power to direct the activities of the VIE and (ii) has the obligation or rights to absorb the VIE's losses or receive its benefits, then the Company would be the primary beneficiary and would consolidate the VIE.

All significant intercompany transactions and accounts have been eliminated.

Reclassifications

Certain amounts from prior years have been reclassified to conform to current-year presentation including reclassifying the accompanying consolidated balance sheets for assets held for sale and the consolidated statements of comprehensive income for discontinued operations.

In 2017, the Company began to separately classify expensed pursuit costs in the Consolidated Statements of Comprehensive Income. These costs, which were reclassed retrospectively for all periods, were formerly classified as general and administrative expense.

Concentration of Credit Risk

As of December 31, 2017, wholly owned properties were leased to 1,091 customers. The geographic locations that comprise greater than 10% of our rental and other revenues were Lehigh Valley/Central PA and Philadelphia. Our customers engage in a wide variety of businesses. No single customer generated more than 4.6% of our consolidated operating rental revenues during 2017.

Real Estate and Depreciation

The properties are recorded at cost and are depreciated using the straight line method over their estimated useful lives. The estimated useful lives are as follows:



Building and improvements		40 years (blended)
Capital improvements		15 - 20 years
Equipment		5 - 10 years
Tenant improvements		Term of the related lease

The Company capitalizes costs associated with development and redevelopment activities, capital improvements, tenant improvements and leasing activities, including compensation costs. Expenditures directly related to the improvement of real estate, including interest and other costs capitalized on development and redevelopment projects and land being readied for development, are included in net real estate and are stated at cost. The Company considers a development property substantially complete upon the completion of tenant build-out, but no later than one year after the completion of major construction activity. These capitalized costs include pre-construction costs essential to the development of the property, construction costs, interest costs, real estate taxes, development related compensation and other costs incurred during the period of development. The determination to capitalize rather than expense costs requires the Company to evaluate the status of the development activity. The total of capitalized compensation costs directly related to development, redevelopment, capital improvements, and tenant improvements for the years ended December 31, 2017, 2016 and 2015 was $5.5 million, $7.2 million and $5.5 million, respectively. Construction related payables at December 31, 2017 and 2016 were $49.3 million and $37.1 million, respectively.

The Company allocates the purchase price of real estate acquired to land, building and improvements and intangibles based on the relative fair value of each component. Lease values for acquired properties are determined based on the present value (using a discount rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to each in-place lease and (ii) management's estimate of fair market lease rates for each corresponding in-place lease ("Market Value Intangible"). Origination values are also assigned to in-place leases, and, where appropriate, value is assigned to customer relationships ("Origination Value Intangible").

Acquisition-related costs for vacant properties are capitalized and included in net real estate at cost. Beginning on October 1, 2016, acquisition-related costs for properties with in-place leases deemed to be asset acquisitions are also capitalized and included in net real estate at cost. Expenditures for maintenance and repairs are charged to operations as incurred.

The Company depreciates the amounts allocated to building and improvements over 40 years and amortizes the amounts allocated to intangibles relating to in-place leases, which are included in deferred financing and leasing costs and other liabilities in the accompanying consolidated balance sheets, over the remaining term of the related leases. Market Value Intangible amortization is recorded as rental revenue. Origination Value Intangible amortization is recorded as depreciation and amortization. This calculation includes both the remaining noncancelable period and any bargain renewal option periods.

Once a property is designated as held for sale, no further depreciation expense is recorded.

The Company evaluates its real estate investments upon occurrence of a significant adverse change in its operations to assess whether any impairment indicators are present that affect the recovery of the recorded value. If indicators of impairment are identified, the Company estimates the future undiscounted cash flows from the use and eventual disposition of the property and compares this amount to the carrying value of the property. If any real estate investment is considered impaired, a loss is recognized to reduce the carrying value of the property to its estimated fair value.

Investments in Unconsolidated Joint Ventures

The Company accounts for its investments in unconsolidated joint ventures using the equity method of accounting as the Company exercises significant influence, but does not control these entities.

Under the equity method of accounting, the net equity investment of the Company is reflected in the accompanying consolidated balance sheets and the Company's share of net income from the joint ventures is included in the accompanying consolidated statements of comprehensive income.

On a periodic basis, management assesses whether there are any indicators that the value of the Company's investments in unconsolidated joint ventures may be other-than-temporarily-impaired. An investment is impaired only if management's estimate of the value of the investment is less than the carrying value of the investment, and such decline in value is deemed to be other-than-temporary. To the extent impairment has occurred, the loss is measured as the excess of the carrying amount of the investment over the estimated fair value of the investment. The estimated fair value of the investments is determined using a discounted cash flow model which is a Level 3 valuation under ASC 820, "Fair Value Measurement." The Company considers a number of assumptions that are subject to economic and market uncertainties including, among others, demand for space, competition for tenants, changes in market rental rates, operating costs, capitalization rates, holding periods and discount rates.

Cash and Cash Equivalents

Highly liquid investments with a maturity of three months or less when purchased are classified as cash equivalents.

Restricted Cash

Restricted cash includes tenant security deposits and escrow funds that the Company maintains pursuant to certain mortgage loans. Restricted cash also includes the undistributed proceeds from the sale of residential land in Kent County, United Kingdom.

Accounts Receivable/Deferred Rent Receivable

The Company's accounts receivable are comprised of rents and charges for property operating costs due from tenants. The Company's deferred rent receivable represents the cumulative difference between rent revenue recognized on a straight line basis and contractual payments due under the terms of tenant leases. The Company periodically performs a detailed review of amounts due from tenants to determine if accounts receivable and deferred rent receivable balances are collectible. Based on this review, accounts receivable and deferred rent receivable are reduced by an allowance for doubtful accounts. The Company considers tenant credit quality and payment history and general economic conditions in determining the allowance for doubtful accounts. If the accounts receivable balance or the deferred rent receivable balance is subsequently deemed uncollectible, the receivable and allowance for doubtful account balance are written off.

Revenue Recognition

The Company earns rental income under operating leases with tenants. Rental income is recognized on a straight line basis over the applicable non-cancelable lease term. Operating expense reimbursements consisting of amounts due from tenants for real estate taxes, utilities and other recoverable costs are recognized as revenue in the period in which the corresponding expenses are incurred.

The Company considers any renewal options in determining the lease term. To the extent a lease includes a tenant option to renew or extend the duration of the lease at a fixed or determinable rental rate, the Company evaluates whether or not that option represents a bargain renewal option by analyzing if there is reasonable assurance at lease inception that the tenant will exercise the option because the rental rate is sufficiently lower than the expected rental rate for equivalent property under similar terms and conditions at the exercise date.

Termination fees (included in rental revenue) are fees that the Company has agreed to accept in consideration for permitting certain tenants to terminate their lease prior to the contractual expiration date. The Company recognizes termination fees during the period that landlord services are rendered in accordance with Securities and Exchange Commission Staff Accounting Bulletin 104, "Revenue Recognition," after the following conditions are met:


a.	the termination agreement is executed,


b.	the termination fee is determinable, and


c.	collectability of the termination fee is assured.

In the fourth quarter of 2016, the Company entered into an agreement relating to the fee development of an office building at its Camden Waterfront project in Camden, NJ. Project revenues and related costs and expenses are presented on a gross basis as "Development service fee income" and "Development service fee expense" in the Consolidated Statements of Comprehensive Income. Additionally, at the same time, the Company began classifying development fees and expenses relating to its fee development arrangements for certain unconsolidated joint venture projects in a manner consistent with the Camden project described above. Previously, development service fee income relating to its unconsolidated joint ventures had been classified as other income and development service fee expense had been classified as general and administrative expense in amounts as follows:



	Nine months ended		Year ended
	September 30, 2016		December 31, 2015
	(unaudited)
Other income	$	3,789	$	6,159
General and administrative expense	$	3,210	$	3,730

Revenue and expense associated with service fee development is accounted for under the percentage of completion method. Revenues are recognized on the percentage of completion method based on applicable costs incurred with respect to each development agreement. The Company uses the relative sales value method to allocate costs and recognize profits from service fee development. Under the relative sales value method, estimates of aggregate project revenues and aggregate project costs are used to determine the allocation of project cost of sales and the resulting profit in each accounting period. In subsequent periods, cost of sale allocations and the resulting profits are adjusted to reflect changes in the actual and estimated costs and revenues of each project. Provisions for estimated losses on uncompleted contracts are recognized immediately in the period in which such losses are determined.

Deferred Financing and Leasing Costs

Costs incurred in connection with the financing of the credit facilities or leasing are capitalized and amortized on a straight line basis over the term of the related loan or lease. Costs incurred in connection with the financing of mortgage loans or unsecured notes are reported as a deduction from the face amount of that liability and amortized on a straight line basis over the term of the related loan. Deferred financing cost amortization is reported as interest expense.

Certain employees of the Company are compensated for leasing services related to the Company's properties. The compensation directly related to these leasing services is capitalized and amortized as a deferred leasing cost over the term of the related lease.

Fair Value of Financial Instruments

ASC 820, Fair Value Measurements and Disclosures, gives guidance on the fair value measurement of a financial asset or liability. Inputs used to develop fair value are classified in one of three categories: Level 1 inputs (quoted prices (unadjusted) in active markets for identical assets or liabilities), Level 2 inputs (inputs other than quoted prices that are observable for the asset or liability, either directly or indirectly) and Level 3 inputs (unobservable inputs for the asset or liability).

The following disclosure of estimated fair value was determined by management using available market information and appropriate valuation methodologies. However, considerable judgment is necessary to interpret market data and develop estimated fair value. Accordingly, the following estimates are not necessarily indicative of the amounts the Company could have realized on disposition of the financial instruments at December 31, 2017 and December 31, 2016. The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts.

The carrying value of cash and cash equivalents, restricted cash, accounts receivable, accounts payable, accrued interest, dividend and distributions payable and other liabilities are reasonable estimates of fair value because of the short-term nature of these instruments. The carrying value of the outstanding amounts under the Company's credit facilities is also a reasonable estimate of fair value because interest rates float at a rate based on LIBOR.

The Company determines the fair value of its interest rate swaps by using the standard methodology of netting discounted future fixed cash payments with the discounted expected variable cash receipts. These variable cash receipts of interest rate swaps are based on expectations of future LIBOR interest rates (forward curves) estimated by observing market LIBOR interest rate curves. This is a Level 2 fair value calculation. Also, credit valuation adjustments are factored into the fair value calculations to account for potential nonperformance risk. These credit valuation adjustments were concluded to be not significant inputs for the fair value calculations for the periods presented. See Note 20 - Derivative Instruments.

The Company used a discounted cash flow model to determine the estimated fair value of its debt as of December 31, 2017 and December 31, 2016. This is a Level 3 fair value calculation. The inputs used in preparing the discounted cash flow model include actual maturity dates and scheduled cash flows as well as estimates for market value discount rates. The Company updates the discounted cash flow model on a quarterly basis to reflect any changes in the Company's debt holdings and changes to discount rate assumptions.

Income Taxes

The Company has elected to be taxed as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended (the "Code"). As a result, the Company generally is not subject to federal income taxation at the corporate level to the extent it distributes annually at least 100% of its REIT taxable income, as defined in the Code, to its shareholders and satisfies certain other organizational and operational requirements. The Company has met these requirements and, accordingly, no provision has been made for federal income taxes in the accompanying consolidated financial statements. If the Company fails to qualify as a REIT in any taxable year, the Company will be subject to federal income tax on its taxable income at regular corporate rates (including any alternative minimum tax) and may not be able to qualify as a REIT for the four subsequent taxable years. Even as a REIT, the Company may still be subject to certain state and local income and property taxes, and to federal income and excise taxes on undistributed taxable income. The Company has considered the provisions of the Tax Cuts and Jobs Act (the "TCJA"), which was signed into law on December 22, 2017 and which generally takes effect for taxable years beginning on or after January 1, 2018, and does not expect the TCJA to have a material impact on its overall business operations or ability to continue to qualify as a REIT.

Several of the Company's subsidiaries are taxable REIT subsidiaries (each a "TRS") and are subject to federal and state income taxes separate from the Company. In general, a TRS may perform additional services for tenants and generally may engage in real estate or non-real estate businesses that are not permitted REIT activities. The Company itself is also subject to tax in certain states and the United Kingdom. Accordingly, the Company recognizes federal, state and foreign income taxes in accordance with US GAAP, as applicable. In addition, the TCJA implemented a one-time deemed repatriation tax on offshore corporate profits, including any such profits which the Company may have accumulated over the years in its offshore TRSs, at the reduced rates of 15.5% on cash assets and 8% on noncash assets. The Company has reviewed its accumulated offshore earnings through December 31, 2017 and does not expect this provision of the TCJA will have a material impact on the Company’s overall financial condition or results of operation.

There are no uncertain tax positions or possibly significant unrecognized tax benefits that are reasonably expected to occur within the next 12 months. The Company's policy is to recognize interest accrued related to unrecognized benefits in interest expense and penalties in other expense. There were no interest or penalties deducted in any of the years ended December 31, 2017, 2016 and 2015 and no interest and penalties accrued at December 31, 2017 or December 31, 2016 which related to any uncertain tax positions or significant unrecognized tax benefits.

Certain of the Company's TRSs had net operating loss ("NOL") carryforwards available of approximately $40.6 million as of December 31, 2017. The TCJA reduced the corporate federal tax rate in the U.S. to 21.0% effective for tax years beginning after December 31, 2017. As such, deferred tax assets and liabilities, where applicable, were remeasured using the lower corporate federal tax rate at December 31, 2017. These NOL carryforwards begin to expire in 2018. After taking into consideration future taxable income and consistent with prior periods, the Company has determined that a valuation allowance for the full carrying value of NOL carryforwards is appropriate.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction, certain state and local jurisdictions, the United Kingdom and (in prior years) Luxembourg. With few exceptions, the Company and its subsidiaries are no longer subject to examination by taxing authorities in these jurisdictions for years prior to 2011.

Share-based Compensation

Share-Based Compensation

Share-based compensation cost is measured at the grant date, based on the fair value of the award, and is recognized as expense over the employees' requisite service period.

Selling, General and Administrative Expenses, Policy [Policy Text Block]

Expensed Pursuit Costs

The Company capitalizes pre-development costs incurred in pursuit of new development opportunities for which the Company currently believes future development is probable. Future development is dependent upon various factors, including zoning and regulatory approval, rental market conditions and construction costs. Initial pre-development costs incurred for pursuits for which future development is not yet considered probable are expensed as incurred. In addition, if the status of a future development by the Company is no longer probable, any capitalized pre-development costs are written off with a charge to expense.

Derivative Financial Instruments

We borrow funds at a combination of fixed and variable rates. Borrowings under our revolving credit facility and certain bank mortgage loans bear interest at variable rates. Our long-term debt typically bears interest at fixed rates. Our interest rate risk management objectives are to limit generally the impact of interest rate changes on earnings and cash flows and to lower our overall borrowing costs. To achieve these objectives, from time to time, we enter into interest rate hedge contracts such as collars, swaps, caps and treasury lock agreements in order to mitigate our interest rate risk with respect to various debt instruments. We generally do not hold or issue these derivative contracts for trading or speculative purposes. The interest rate on all of our variable rate debt is generally adjusted at one or three month intervals, subject to settlements under interest rate hedge contracts.

Interest rate swaps involve the receipt of variable-rate amounts from a counterparty in exchange for making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive loss (for the Trust) and general partner's equity and limited partners' equity - common units (for the Operating Partnership) and is subsequently reclassified into interest expense in the period that the hedged forecasted transaction affects earnings.

Foreign Currency

The functional currency of the Company's United Kingdom operations is pounds sterling. The Company translates the financial statements for the United Kingdom operations into US dollars. For the Trust, gains and losses resulting from this translation are included in accumulated other comprehensive loss as a separate component of shareholders' equity and a proportionate amount of gain or loss is allocated to noncontrolling interest - operating partnership - common units. For the Operating Partnership, gains and losses resulting from this translation are included in general partner's equity and limited partners' equity - common units. Upon sale or upon complete or substantially complete liquidation of the Company's foreign investment, the gain or loss on the sale will include the cumulative translation adjustments that have been previously recorded in accumulated other comprehensive loss and noncontrolling interest - operating partnership - common units (for the Trust) and in general partner's equity and limited partners' equity - common units (for the Operating Partnership).

Comprehensive Income

Comprehensive income, as reflected on the consolidated statements of comprehensive income, is defined as all changes in equity during each period except for those resulting from investments by or distributions to shareholders. Accumulated other comprehensive loss, as reflected on the Company's consolidated balance sheets and consolidated statements of equity, reflects the effective portion of the cumulative changes in the fair value of derivatives in qualifying cash flow hedge relationships as well as gains and losses resulting from foreign currency translation.

Sales of Real Estate

The Company accounts for the sale of real estate assets and any related gain recognition in accordance with the accounting guidance applicable to sales of real estate, which establishes standards for recognition of profit on all real estate sales transactions, other than retail land sales. The Company recognizes the sale, and associated gain or loss from the disposition, provided that the earnings process is complete and the Company is not obligated to perform significant activities after the sale.

Earnings Per Share/Unit

Earnings Per Share of the REIT

Basic earnings per share is calculated by dividing the income available to common shareholders for the period by the weighted average number of common shares outstanding during the period using the two class method. Diluted earnings per share is calculated by dividing the net income available to common shareholders for the period by the weighted average number of common and dilutive securities outstanding during the period.

Recently Issued Accounting Standards

In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"), which supersedes nearly all existing revenue recognition guidance (except revenue in the scope of other accounting standards, including standards related to leasing). Subsequently, the FASB issued the following standards related to ASU 2014-09: ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations; ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing; ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients; and ASU 2017-13, Revenue from Contracts with Customers (Topic 606): Amendments to SEC Paragraphs Pursuant to the Staff Announcement at the July 20, 2017 EITF Meeting and Rescission of Prior SEC Staff Announcements and Observer Comments (collectively, the “New Revenue Standards”).

The New Revenue Standards clarify the required factors that an entity must consider when recognizing revenue and require additional disclosures concerning contracts with customers, judgments concerning revenue recognition, and assets recognized for the costs to obtain or fulfill a contract. The Company concluded that there are no revenue streams from its lease agreements that are covered by the New Revenue Standards with the exception of non-lease components as further discussed below. Once the new guidance setting forth principles for the recognition, measurement, presentation and disclosure of leases goes into effect on January 1, 2019, the Company believes that the New Revenue Standards will apply to components of revenue due under leases that are deemed to be non-lease components (such as common area maintenance and provision of utilities), which could affect the recognition pattern for such revenue.

The Company has completed its evaluation of the New Revenue Standards' impact on its remaining revenue streams. The Company adopted this standard effective January 1, 2018 using the modified retrospective approach, which requires applying the new standard to all existing contracts not yet completed as of the effective date and recording a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The New Revenue Standards will not have a material impact on the measurement and recognition of gains and losses on the sale of properties. The New Revenue Standards will not have a material impact on the amount and timing of recognizing its development service fee income, which is currently accounted for under the percentage of completion method based on applicable costs incurred and estimated to be incurred. The Company has completed its evaluation of the standard's impact on its revenue streams. The Company does not believe the adoption of the New Revenue Standards will have a material impact on the consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases ("ASU 2016-02"). ASU 2016-02 amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets and making targeted changes to lessor accounting. ASU 2016-02 is effective for the Company beginning January 1, 2019. Early adoption of ASU 2016-02 is permitted. The standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. For leases in which the Company is the lessor, the standard requires that the lease and non-lease components of the lease agreement should be separated. Revenue related to the lease component of the contract will be recognized on a straight-line basis, while revenue related to the non-lease component will be recognized under the provisions of the New Revenue Standards. For lease agreements longer than one year in which the Company is the lessee, the Company will measure the present value of the future lease payments and recognize a right-of-use asset and corresponding lease liability on its balance sheet. In addition, the new standard states that only direct leasing costs may be capitalized. The Company is evaluating the impact ASU 2016-02 will have on its financial position and results of operations.

In March 2016, the FASB issued ASU 2016-05, Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships ("ASU 2016-05"). ASU 2016-05 states that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under FASB Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The Company adopted ASU 2016-05 beginning January 1, 2017 on a prospective basis. The adoption of ASU 2016-05 did not have a material impact on its financial position and results of operations.

In March 2016, the FASB issued ASU 2016-09. ASU 2016-09 is designed to simplify several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The Company adopted ASU 2016-09 beginning January 1, 2017. Certain amendments in the standard were applied retrospectively and certain amendments were applied prospectively. The adoption of ASU 2016-09 did not have a material impact on its financial position and results of operations. The impact of the implementation of ASU 2016-09 is shown in the table below.

In August 2016, the FASB issued ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”). ASU 2016-15 is designed to clarify how entities should classify cash receipts and cash payments in the statement of cash flows. ASU 2016-15 is effective for the Company beginning January 1, 2018. Early adoption of ASU 2016-15 is permitted. The standard requires retrospective application unless it is impracticable to do so. The Company is evaluating the impact ASU 2016-15 will have on its statement of cash flows.

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 230) - Restricted Cash (“ASU 2016-18”) , which requires that restricted cash and cash equivalents be included with cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the consolidated statements of cash flows. The new standard is effective for public entities for fiscal years beginning after December 15, 2017 and for interim periods therein, with early adoption permitted. The Company adopted ASU 2016-18 as of December 31, 2017.

The impact of the implementation of ASU 2016-18 and ASU 2016-09 was as follows:



	Year Ended December 31,
	2017			2016			2015
Net cash provided by operating activities (prior to adoption of ASU 2016-09 and ASU 2016-18)	$	331,337		$	333,021		$	385,366
Impact of including restricted cash with cash and cash equivalents	187			2,669			(10,478		)
Impact of including shares related to tax withholdings in financing activities	5,107			5,372			4,233
Net cash provided by operating activities (after adoption of ASU 2016-09 and ASU 2016-18)	$	336,631		$	341,062		$	379,121

Net cash (used in) provided by investing activities (prior to adoption of ASU 2016-18)	$	(465,652	)	$	613,402		$	(89,660	)
Impact of including restricted cash with cash and cash equivalents	—			1,525			—
Net cash (used in) provided by investing activities (after adoption of ASU 2016-18)	$	(465,652	)	$	614,927		$	(89,660	)

Net cash provided by (used in) financing activities (prior to adoption of ASU 2016-09)	$	101,338		$	(934,135	)	$	(327,627	)
Impact of including shares related to tax withholdings in financing activities	(5,107		)	(5,372		)	(4,233		)
Net cash provided by (used in) financing activities (prior to adoption of ASU 2016-09)	$	96,231		$	(939,507	)	$	(331,860	)

In February 2017, the FASB issued ASU 2017-05, Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets ("ASU 2017-05"). ASU 2017-05 is designed to provide guidance on how to recognize gain and losses on sales, including partial sale, of nonfinancial assets to noncustomers. The Company adopted ASU 2017-05 effective January 1, 2018 on a modified retrospective method and the adoption will not have a material effect on the Company’s consolidated financial statements.

In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting ("ASU 2017-09"). ASU 2017-09 clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. ASU 2017-09 is effective for the Company beginning January 1, 2018. Early adoption is permitted. The new guidance will be applied prospectively to awards modified on or after the adoption date. The Company does not believe the adoption of the ASU 2017-09 will have a material impact on the consolidated financial statements.

In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities ("ASU 2017-12"). ASU 2017-12 is designed to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for the Company beginning January 1, 2019. Early adoption is permitted using a modified retrospective transition method. This adoption method will require the Company to recognize the cumulative effect of initially applying ASU 2017-12 as an adjustment to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the update. The Company is evaluating the impact ASU 2017-12 will have on the Company's financial position and results of operations.

Interest Expense Allocated to Discontinued Operations

Interest expense has been allocated to discontinued operations. The allocation of interest expense to discontinued operations was based on the ratio of net assets sold and held for sale (without continuing involvement) to the sum of total net assets plus consolidated debt.

Accounting for the Impairment or Disposal of Long-Lived Assets

The Company determined these impairments based on third party offer prices and quoted offer prices for comparable transactions which are Level 2 and Level 3 inputs, respectively, according to the fair value hierarchy established in ASC 820. These measurements have occurred throughout the respective periods as circumstances arise, and the resulting estimates of fair value are not necessarily reflective of measurements at the period’s end. The Company has evaluated each of its properties and land held for development and has determined that there were no additional valuation adjustments necessary at December 31, 2017. The Company applied reasonable estimates and judgments in determining the level of impairments recognized. Should external or internal circumstances change requiring the need to shorten the holding periods or adjust the estimated future cash flows of the Company’s assets, the Company could be required to record impairment charges in the future.

Liberty Property Limited Partnership [Member]

Earnings Per Share, Basic and Diluted [Line Items]

Earnings Per Share/Unit

Earnings Per Unit of the Operating Partnership

Basic earnings per unit is calculated by dividing the income available to common unitholders for the period by the weighted average number of common units outstanding during the period using the two class method. Diluted earnings per unit is calculated by dividing the income available to common unitholders for the period by the weighted average number of common and dilutive securities outstanding during the period.