Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The following disclosure regarding certain of our significant accounting policies should be read in conjunction with Note 2 to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019, which provides additional information with regard to the accounting policies set forth herein and other significant accounting policies. Impairment of Long-Lived Assets For the three months ended March 31, 2019, the Company recorded impairment charges totaling $12.6 million. During the first quarter of 2019, management and the Company’s Board of Trustees formally approved the “Atlanta Major Market Strategy” plan which included the partial redevelopment of an existing warehouse facility. The partial redevelopment required the demolition of approximately 75% of the current warehouse, which was unused. We have continued to operate as normal during the redevelopment. As a result of this initiative, the Company wrote off the carrying value of the portion of the warehouse no longer in use resulting in an impairment charge of $9.6 million of Warehouse segment assets. Additionally, during the first quarter of 2019 the Company recorded an impairment charge of $2.9 million of Warehouse segment assets related to a domestic idle warehouse facility in anticipation of a potential future sale of the asset. The estimated fair value of this asset was determined based on ongoing negotiations with prospective buyers. The sale of this property was completed during the second quarter of 2019. The impairment charges are included in the “Impairment of long-lived assets” line item of the Condensed Consolidated Statements of Operations for the three months ended March 31, 2019. There were no impairment charges recorded during the three months ended March 31, 2020. Capitalization of Costs Project costs that are clearly associated with the development of properties are capitalized as incurred. Project costs include all costs directly associated with the development of a property, including construction costs, interest, and costs of personnel working on the project. Costs that do not clearly relate to the projects under development are not capitalized and are charged to expense as incurred. Capitalization of costs begins when the activities necessary to get the development project ready for its intended use commence, which include costs incurred before the beginning of construction. Capitalization of costs ceases when the development project is substantially complete and ready for its intended use. Determining when a development project commences and when it is substantially complete and ready for its intended use involves a degree of judgment. We generally consider a development project to be substantially complete and ready for its intended use upon receipt of a certificate of occupancy. If and when development of a property is suspended pursuant to a formal change in the planned use of the property, we will evaluate whether the accumulated costs exceed the estimated value of the project and write off the amount of any such excess accumulated costs. For a development project that is suspended for reasons other than a formal change in the planned use of such property, the accumulated project costs are written off. Capitalized costs are allocated to the specific components of a project that are benefited. We capitalized interest of $0.8 million for each of the three months ended March 31, 2020 and 2019. During each of the three months ended March 31, 2020 and 2019, we capitalized amounts relating to compensation and travel expense of employees direct and incremental to development of properties of approximately $0.1 million and $0.2 million, respectively. Business Combinations For business combinations, the excess of purchase price over the net fair value of assets acquired and liabilities assumed is recorded as goodwill. In an asset acquisition where we have determined that the cost incurred differs from the fair value of the net assets acquired, we assess whether we have appropriately determined the fair value of the assets and liabilities acquired and we also confirm that all identifiable assets have been appropriately identified and recognized. After completing this assessment, we allocate the difference on a relative fair value basis to all assets acquired except for financial assets (as defined in ASC 860, Transfers and Servicing), deferred taxes, and assets defined as “current” (as defined in ASC 210, Balance Sheet). Whether the acquired business is being accounted for as a business combination or an asset acquisition, the determination of fair values of identifiable assets and liabilities requires estimates and the use of valuation techniques. The Company estimates the fair values using observable inputs classified as Level 2 and unobservable inputs classified as Level 3 of the fair value hierarchy. Significant judgment is involved specifically in determining the estimated fair value of the acquired land and buildings and improvements and intangible assets. For intangible assets, we typically use the excess earnings method. Significant estimates used in valuing intangible assets acquired in a business combination include, but are not limited to, revenue growth rates, customer attrition rates, operating costs and margins, capital expenditures, tax rates, long-term growth rates and discount rates. For land and buildings and improvements, we used a combination of methods including the cost approach to value buildings and improvements and the sales comparison approach to value the underlying land. Significant estimates used in valuing land and buildings and improvements acquired in a business combination include, but are not limited to estimates of indirect costs and entrepreneurial profit, which were added to the replacement cost of the acquired assets in order to estimate their fair value in the market. Refer to Note 3 for the disclosures related to recent acquisitions accounted for as a business combination. Asset Acquisitions We acquired PortFresh in an asset acquisition on February 1, 2019 for $35.2 million, net of cash. The cost incurred in connection with this asset acquisition was allocated primarily to property, buildings and equipment. Additionally, we acquired MHW in an asset acquisition on November 19, 2019 for $50.8 million, net of cash. The cost incurred in connection with this asset acquisition was allocated primarily to $50.1 million of land, buildings and equipment, $0.6 million of an assembled workforce intangible asset and $0.1 million of other assets and liabilities, net. Additionally, the purchase agreement included a call option to purchase land from the holder of the ground lease for $4.1 million, which was exercised in January 2020. Recently Adopted Accounting Standards Fair Value Measurement - Disclosure Framework In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. This ASU modifies the disclosure requirements on fair value measurements. The ASU removes the requirement to disclose: the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; the policy for timing of transfers between levels; and the valuation processes for Level 3 fair value measurements. The ASU requires disclosure of changes in unrealized gains and losses for the period included in other comprehensive income (loss) for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For public business entities, this guidance is effective for fiscal years beginning after December 15, 2019 with early adoption permitted. The Company adopted this standard effective January 1, 2020 on a prospective basis, and it did not have a material impact on its consolidated financial statements. Collaborative Arrangements In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the interaction between Topic 808 and Topic 606. ASU 2018-18 clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer and precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. For public business entities, these amendments are effective for fiscal years beginning after December 15, 2019, and interim periods therein. The Company adopted this standard effective January 1, 2020, and it did not have a material impact on its consolidated financial statements. Credit Losses Effective January 1, 2020, we adopted ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, using the modified retrospective transition method. This ASU amends the impairment model to utilize an expected loss methodology in place of the incurred loss methodology for financial instruments, including trade receivables, and off-balance sheet credit exposures. The amendment requires entities to consider a broader range of information to estimated expected credit losses, which may result in earlier recognition of losses. Upon adoption of the new standard, the Company recorded a non-cash cumulative effect adjustment to the opening accumulated deficit and distributions in excess of net earnings of $0.5 million as of January 1, 2020. As of March 31, 2020, we had $536.8 million of assets in the scope of the credit loss standard. These assets consist primarily of cash equivalents measured at amortized cost and trade and other receivables. Counterparties associated with these assets are generally highly rated. The substantial majority of the allowance recorded on the aforementioned in-scope assets relates to our trade receivables and totaled $7.4 million as of March 31, 2020. Financial Instruments In March 2020, FASB issued ASU 2020-03, Codification Improvements to Financial Instruments. This ASU improves and clarifies various financial instruments topics, including the current expected credit losses (CECL) standard issued in 2016. The ASU includes seven different issues that describe the areas of improvement and the related amendments to GAAP, intended to make the standards easier to understand and apply by eliminating inconsistencies and providing clarifications. The amendments have different effective dates. The Company adopted this standard effective January 1, 2020, and it did not have a material impact on its consolidated financial statements. Future Adoption of Accounting Standards Defined Benefit Plans In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework – Changes to the Disclosure Requirements for Defined Benefit Plans. This update amends ASC 715 to remove disclosures that are no longer considered cost beneficial, clarifies the specific requirements of disclosures, and adds disclosure requirements identified as relevant to defined benefit pension and other postretirement plans. The ASU’s changes related to disclosures are part of the FASB’s disclosure framework project. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted for all entities and the amendments in this update are required to be applied on a retrospective basis to all periods presented. The Company does not expect the provisions of ASU 2018-14 will have a material impact on its consolidated financial statements. Simplifying the Accounting for Income Taxes In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (Topic 740). This ASU is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020; however, early adoption is permitted for all entities. The Company continues to assess the impact of adopting this standard and does not believe the adoption of ASU 2019-12 will have a material effect on its consolidated financial statements. Reference Rate Reform In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848). This ASU contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. During the first quarter of 2020, the Company has elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. Investments - equity securities; Investments—Equity Method and Joint Ventures; Derivatives and Hedging In January 2020, the FASB issued ASU 2020-01, Investments—Equity Securities (Topic 321), Investments—Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815). The amendments in this ASU clarify the interaction between the accounting for investments in equity securities, equity method investments and certain derivatives instruments. The ASU is expected to reduce diversity in practice and increase comparability of the accounting for these interactions. This ASU is effective for fiscal years beginning after December 15, 2020. The adoption of this ASU is not expected to have any impact on the Company's financial statements.

The following disclosure regarding certain of our significant accounting policies should be read in conjunction with Note 2 to the consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019, which provides additional information with regard to the accounting policies set forth herein and other significant accounting policies.

For the three months ended March 31, 2019, the Company recorded impairment charges totaling $12.6 million. During the first quarter of 2019, management and the Company’s Board of Trustees formally approved the “Atlanta Major Market Strategy” plan which included the partial redevelopment of an existing warehouse facility. The partial redevelopment required the demolition of approximately 75% of the current warehouse, which was unused. We have continued to operate as normal during the redevelopment. As a result of this initiative, the Company wrote off the carrying value of the portion of the warehouse no longer in use resulting in an impairment charge of $9.6 million of Warehouse segment assets. Additionally, during the first quarter of 2019 the Company recorded an impairment charge of $2.9 million of Warehouse segment assets related to a domestic idle warehouse facility in anticipation of a potential future sale of the asset. The estimated fair value of this asset was determined based on ongoing negotiations with prospective buyers. The sale of this property was completed during the second quarter of 2019. The impairment charges are included in the “Impairment of long-lived assets” line item of the Condensed Consolidated Statements of Operations for the three months ended March 31, 2019. There were no impairment charges recorded during the three months ended March 31, 2020.

Project costs that are clearly associated with the development of properties are capitalized as incurred. Project costs include all costs directly associated with the development of a property, including construction costs, interest, and costs of personnel working on the project. Costs that do not clearly relate to the projects under development are not capitalized and are charged to expense as incurred.

Capitalization of costs begins when the activities necessary to get the development project ready for its intended use commence, which include costs incurred before the beginning of construction. Capitalization of costs ceases when the development project is substantially complete and ready for its intended use. Determining when a development project commences and when it is substantially complete and ready for its intended use involves a degree of judgment. We generally consider a development project to be substantially complete and ready for its intended use upon receipt of a certificate of occupancy. If and when development of a property is suspended pursuant to a formal change in the planned use of the property, we will evaluate whether the accumulated costs exceed the estimated value of the project and write off the amount of any such excess accumulated costs. For a development project that is suspended for reasons other than a formal change in the planned use of such property, the accumulated project costs are written off. Capitalized costs are allocated to the specific components of a project that are benefited.

We capitalized interest of $0.8 million for each of the three months ended March 31, 2020 and 2019. During each of the three months ended March 31, 2020 and 2019, we capitalized amounts relating to compensation and travel expense of employees direct and incremental to development of properties of approximately $0.1 million and $0.2 million, respectively.

For business combinations, the excess of purchase price over the net fair value of assets acquired and liabilities assumed is recorded as goodwill. In an asset acquisition where we have determined that the cost incurred differs from the fair value of the net assets acquired, we assess whether we have appropriately determined the fair value of the assets and liabilities acquired and we also confirm that all identifiable assets have been appropriately identified and recognized. After completing this assessment, we allocate the difference on a relative fair value basis to all assets acquired except for financial assets (as defined in ASC 860, Transfers and Servicing), deferred taxes, and assets defined as “current” (as defined in ASC 210, Balance Sheet).

Whether the acquired business is being accounted for as a business combination or an asset acquisition, the determination of fair values of identifiable assets and liabilities requires estimates and the use of valuation techniques. The Company estimates the fair values using observable inputs classified as Level 2 and unobservable inputs classified as Level 3 of the fair value hierarchy. Significant judgment is involved specifically in determining the estimated fair value of the acquired land and buildings and improvements and intangible assets. For intangible assets, we typically use the excess earnings method. Significant estimates used in valuing intangible assets acquired in a business combination include, but are not limited to, revenue growth rates, customer attrition rates, operating costs and margins, capital expenditures, tax rates, long-term growth rates and discount rates. For land and buildings and improvements, we used a combination of methods including the cost approach to value buildings and improvements and the sales comparison approach to value the underlying land. Significant estimates used in valuing land and buildings and improvements acquired in a business combination include, but are not limited to estimates of indirect costs and entrepreneurial profit, which were added to the replacement cost of the acquired assets in order to estimate their fair value in the market.

We acquired PortFresh in an asset acquisition on February 1, 2019 for $35.2 million, net of cash. The cost incurred in connection with this asset acquisition was allocated primarily to property, buildings and equipment. Additionally, we acquired MHW in an asset acquisition on November 19, 2019 for $50.8 million, net of cash. The cost incurred in connection with this asset acquisition was allocated primarily to $50.1 million of land, buildings and equipment, $0.6 million of an assembled workforce intangible asset and $0.1 million of other assets and liabilities, net. Additionally, the purchase agreement included a call option to purchase land from the holder of the ground lease for $4.1 million, which was exercised in January 2020.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. This ASU modifies the disclosure requirements on fair value measurements. The ASU removes the requirement to disclose: the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; the policy for timing of transfers between levels; and the valuation processes for Level 3 fair value measurements. The ASU requires disclosure of changes in unrealized gains and losses for the period included in other comprehensive income (loss) for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For public business entities, this guidance is effective for fiscal years

In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the interaction between Topic 808 and Topic 606. ASU 2018-18 clarifies that certain transactions between participants in a collaborative arrangement should be accounted for under ASC 606 when the counterparty is a customer and precludes an entity from presenting consideration from a transaction in a collaborative arrangement as revenue from contracts with customers if the counterparty is not a customer for that transaction. For public business entities, these amendments are effective for fiscal years beginning after December 15, 2019, and interim periods therein. The Company adopted this standard effective January 1, 2020, and it did not have a material impact on its consolidated financial statements.

Effective January 1, 2020, we adopted ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, using the modified retrospective transition method. This ASU amends the impairment model to utilize an expected loss methodology in place of the incurred loss methodology for financial instruments, including trade receivables, and off-balance sheet credit exposures. The amendment requires entities to consider a broader range of information to estimated expected credit losses, which may result in earlier recognition of losses. Upon adoption of the new standard, the Company recorded a non-cash cumulative effect adjustment to the opening accumulated deficit and distributions in excess of net earnings of $0.5 million as of January 1, 2020.

As of March 31, 2020, we had $536.8 million of assets in the scope of the credit loss standard. These assets consist primarily of cash equivalents measured at amortized cost and trade and other receivables. Counterparties associated with these assets are generally highly rated. The substantial majority of the allowance recorded on the aforementioned in-scope assets relates to our trade receivables and totaled $7.4 million as of March 31, 2020.

In March 2020, FASB issued ASU 2020-03, Codification Improvements to Financial Instruments. This ASU improves and clarifies various financial instruments topics, including the current expected credit losses (CECL) standard issued in 2016. The ASU includes seven different issues that describe the areas of improvement and the related amendments to GAAP, intended to make the standards easier to understand and apply by eliminating inconsistencies and providing clarifications. The amendments have different effective dates. The Company adopted this standard effective January 1, 2020, and it did not have a material impact on its consolidated financial statements.

In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework – Changes to the Disclosure Requirements for Defined Benefit Plans. This update amends ASC 715 to remove disclosures that are no longer considered cost beneficial, clarifies the specific requirements of disclosures, and adds disclosure requirements identified as relevant to defined benefit pension and other postretirement plans. The ASU’s changes related to disclosures are part of the FASB’s disclosure framework project. This guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted for all entities and the amendments in this update are required

In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (Topic 740). This ASU is intended to simplify various aspects related to accounting for income taxes. ASU 2019-12 removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020; however, early adoption is permitted for all entities. The Company continues to assess the impact of adopting this standard and does not believe the adoption of ASU 2019-12 will have a material effect on its consolidated financial statements.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848). This ASU contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. During the first quarter of 2020, the Company has elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur.

In January 2020, the FASB issued ASU 2020-01, Investments—Equity Securities (Topic 321), Investments—Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815). The amendments in this ASU clarify the interaction between the accounting for investments in equity securities, equity method investments and certain derivatives instruments. The ASU is expected to reduce diversity in practice and increase comparability of the accounting for these interactions. This ASU is effective for fiscal years beginning after December 15, 2020. The adoption of this ASU is not expected to have any impact on the Company's financial statements.