Columbia Property Trust (CXP) 10-Q 29 Apr 21 2021 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2021	Apr. 23, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-36113
Entity Registrant Name	COLUMBIA PROPERTY TRUST, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	20-0068852
Entity Address, Address Line One	315 Park Avenue South
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10010
City Area Code	212
Local Phone Number	687-0800
Title of 12(b) Security	Common Stock
Trading Symbol	CXP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		114,869,125
Entity Central Index Key	0001252849
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Real estate assets, at cost:
Land	$ 809,843	$ 809,843
Buildings and improvements, less accumulated depreciation of $318,017 and $303,764, as of March 31, 2021 and December 31, 2020, respectively	1,525,222	1,537,683
Intangible lease assets, less accumulated amortization of $57,970 and $57,947, as of March 31, 2021 and December 31, 2020, respectively	43,663	46,075
Construction in progress	99,729	83,943
Total real estate assets	2,478,457	2,477,544
Operating lease assets	38,737	39,165
Investments in unconsolidated joint ventures	1,295,419	1,295,800
Cash and cash equivalents	27,093	61,882
Tenant receivables	3,320	2,540
Straight-line rent receivable	75,744	74,051
Prepaid expenses and other assets	39,718	42,285
Intangible lease origination costs, less accumulated amortization of $35,662 and $35,161, as of March 31, 2021 and December 31, 2020, respectively	20,152	21,451
Deferred lease costs, less accumulated amortization of $19,737 and $18,669, as of March 31, 2021 and December 31, 2020, respectively	70,752	71,800
Total assets	4,049,392	4,086,518
Liabilities:
Line of credit and notes payable, net of unamortized deferred financing costs of $1,316 and $1,470, as of March 31, 2021 and December 31, 2020, respectively	572,684	558,530
Bonds payable, net of discounts of $898 and $943 and unamortized deferred financing costs of $2,801 and $2,954, as of March 31, 2021 and December 31, 2020, respectively	696,301	696,103
Operating lease liabilities	1,801	2,185
Accounts payable, accrued expenses, and accrued capital expenditures	82,333	91,493
Dividends payable	0	24,038
Deferred income	16,315	16,155
Intangible lease liabilities, less accumulated amortization of $7,582 and $8,867, as of March 31, 2021 and December 31, 2020, respectively	13,699	14,420
Total liabilities	1,383,133	1,402,924
Commitments and Contingencies (Note 7)	0	0
Equity:
Common stock, $0.01 par value, 225,000,000 shares authorized, 114,869,772 and 114,453,379 shares issued and outstanding, as of March 31, 2021 and December 31, 2020, respectively	1,149	1,145
Additional paid-in capital	4,377,157	4,376,116
Cumulative distributions in excess of earnings	(1,773,457)	(1,749,811)
Cumulative other comprehensive loss	(13,704)	(18,201)
Total stockholders' equity attributable to Columbia Property Trust	2,591,145	2,609,249
Noncontrolling interest in Columbia Operating Partnership	70,307	69,414
Noncontrolling interest in consolidated joint venture	4,807	4,931
Total equity	2,666,259	2,683,594
Total liabilities and equity	$ 4,049,392	$ 4,086,518

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Building and improvements, accumulated depreciation	$ 318,017	$ 303,764
Intangible lease assets, accumulated amortization	57,970	57,947
Intangible lease origination costs, accumulated amortization	35,662	35,161
Deferred lease costs, accumulated amortization	19,737	18,669
Deferred financing costs, net	1,316	1,470
Bonds payable discount	898	943
Intangible lease liabilities, accumulated amortization	$ 7,582	$ 8,867
Common stock, par value (dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	114,869,772	114,453,379
Common stock, shares outstanding	114,869,772	114,453,379
Term Loans
Deferred financing costs, net	$ 1,316	$ 1,470
Bonds Payable
Deferred financing costs, net	$ 2,801	$ 2,954

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Lease revenues	$ 54,309	$ 68,007
Revenues	64,388	76,254
Expenses:
Property operating costs	20,828	22,697
Depreciation	16,531	18,330
Amortization	4,844	6,721
General and administrative	9,776	11,782
Strategic review costs	2,356	0
Management fee expenses	9,269	6,945
Acquisition and restructuring costs (Note 3)	0	12,081
Costs and expenses	63,604	78,556
Other Income (Expense):
Interest expense	(7,536)	(9,555)
Interest and other expense	(239)	(158)
Income tax benefit	329	2,243
Income from unconsolidated joint ventures	7,107	2,656
Gain on sale of real estate assets	0	13,344
Nonoperating income (expense)	(339)	8,530
Net income	445	6,228
Less: net income attributable to noncontrolling interest in Columbia Operating Partnership	(97)	(71)
Less: net loss attributable to noncontrolling interest in consolidated joint venture	129	133
Net income attributable to common stockholders	$ 477	$ 6,290
Per-Share Information – Basic:
Net income (loss) (dollars per share)	$ 0	$ 0.05
Weighted-average common shares outstanding - basic (in shares)	114,115	114,471
Per-Share Information – Diluted:
Net income (loss) (dollars per share)	$ 0	$ 0.05
Weighted-average common shares outstanding - diluted (in shares)	117,851	114,486
Management fee revenues
Revenues:
Other property income	$ 10,079	$ 8,240
Other property income
Revenues:
Other property income	$ 0	$ 7

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 445	$ 6,228
Market value adjustments to interest rate swaps	4,624	(19,993)
Comprehensive income (loss)	5,069	(13,765)
Less: market value adjustments to interest rate swaps attributable to noncontrolling interest in Columbia Operating Partnership	(127)	585
Less: net income attributable to noncontrolling interest in Columbia Operating Partnership	(97)	(71)
Less: net loss attributable to noncontrolling interest in consolidated joint venture	129	133
Comprehensive income (loss) attributable to common stockholders	$ 4,974	$ (13,118)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Cumulative Distributions in Excess of Earnings	Cumulative Other Comprehensive Income (Loss)	Total Equity	Noncontrolling InterestsColumbia Operating Partnership	Noncontrolling InterestsConsolidated Joint Venture
Beginning balance (in shares) at Dec. 31, 2019		115,280,000
Beginning balance, value at Dec. 31, 2019	$ 2,628,617	$ 1,153	$ 4,392,322	$ (1,769,234)	$ (1,101)	$ 2,623,140	$ 0	$ 5,477
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchases of operating partnership units (in shares)		(1,194,000)
Repurchases of Operating Partnership Units	(23,276)	$ (12)	(23,264)			(23,276)
Issuance of noncontrolling interest in Columbia Operating Partnership	55,306						55,306
Issuance of common stock and Operating Partnership Units to directors and employees, and amortized (net of income tax withholdings) (in shares)		327,000
Issuance of common stock and Operating Partnership Units to directors and employees, and amortized (net of income tax withholdings)	2,458	$ 3	97			100	2,358
Contributions from noncontrolling interests	16							16
Distributions to common stockholders and Operating Partnership Unit holders	(24,860)			(24,175)		(24,175)	(685)
Consolidated joint venture partnership interest acquired through investment in the Real Estate Funds	(109)							(109)
Net Income (Loss)	6,228			6,290		6,290	71	(133)
Market value adjustments to interest rate swaps	(19,993)				(19,408)	(19,408)	(585)
Ending balance (in shares) at Mar. 31, 2020		114,413,000
Ending balance, value at Mar. 31, 2020	$ 2,624,387	$ 1,144	4,369,155	(1,787,119)	(20,509)	2,562,671	56,465	5,251
Beginning balance (in shares) at Dec. 31, 2020	114,453,379	114,453,000
Beginning balance, value at Dec. 31, 2020	$ 2,683,594	$ 1,145	4,376,116	(1,749,811)	(18,201)	2,609,249	69,414	4,931
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchases of Operating Partnership Units	(282)		199			199	(481)
Issuance of common stock and Operating Partnership Units to directors and employees, and amortized (net of income tax withholdings) (in shares)		417,000
Issuance of common stock and Operating Partnership Units to directors and employees, and amortized (net of income tax withholdings)	2,677	$ 4	842			846	1,831
Contributions from noncontrolling interests	5							5
Distributions to common stockholders and Operating Partnership Unit holders	(24,804)			(24,123)		(24,123)	(681)
Net Income (Loss)	445			477		477	97	(129)
Market value adjustments to interest rate swaps	$ 4,624				4,497	4,497	127
Ending balance (in shares) at Mar. 31, 2021	114,869,772	114,870,000
Ending balance, value at Mar. 31, 2021	$ 2,666,259	$ 1,149	$ 4,377,157	$ (1,773,457)	$ (13,704)	$ 2,591,145	$ 70,307	$ 4,807

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Common Stock | Columbia Operating Partnership
Distributions to common stockholders per share (dollars per share)	$ 0.21	$ 0.21

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flows From Operating Activities:
Net income	$ 445	$ 6,228
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities:
Straight-line rental income	(1,907)	(3,394)
Lease revenues reversed for doubtful accounts – straight-line rental income	213	0
Lease revenues reserved for doubtful accounts – tenant receivables	1,340	8
Noncash operating lease expense	44	82
Depreciation	16,531	18,330
Amortization	4,335	5,330
Noncash interest expense	643	642
Gain on sale of real estate assets	0	(13,344)
Income from unconsolidated joint ventures	(7,107)	(2,656)
Distributions of earnings from unconsolidated joint ventures	7,750	6,996
Market value adjustment to investment in Real Estate Funds	239	160
Stock based compensation expense	4,144	4,657
Changes in assets and liabilities, net of acquisitions and dispositions:
Increase in tenant receivables, net	(2,120)	(1,710)
Decrease (increase) in prepaid expenses and other assets	2,241	(235)
Decrease in accounts payable and accrued expenses	(7,710)	(4,605)
Decrease (increase) in deferred income	160	(342)
Net cash provided by operating activities	19,241	16,147
Cash Flows From Investing Activities:
Net proceeds from the sale of real estate	0	250,822
Normandy Acquisition (Note 3)	0	(13,971)
Capital improvement and development costs	(16,627)	(23,583)
Deferred lease costs paid	(297)	(3,965)
Investments in unconsolidated joint ventures	(8,138)	(43,641)
Investments in real estate-related funds	(259)	(253)
Distributions from unconsolidated joint ventures	7,877	6,487
Net cash provided by (used in) investing activities	(17,444)	171,896
Cash Flows From Financing Activities:
Financing costs paid	0	(5)
Proceeds from lines of credit and notes payable	14,000	347,000
Repayments of lines of credit and notes payable	0	(180,000)
Contributions from consolidated joint venture partner	5	16
Distributions paid to stockholders and OP unit holders	(48,842)	(49,069)
Redemptions of common stock and OP units	(1,749)	(25,474)
Net cash provided by (used in) financing activities	(36,586)	92,468
Net increase (decrease) in cash and cash equivalents	(34,789)	280,511
Cash and cash equivalents, beginning of period	61,882	12,303
Cash and cash equivalents, end of period	$ 27,093	$ 292,814

Organization

Organization	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Columbia Property Trust, Inc. ("Columbia Property Trust" or "Columbia") (NYSE: CXP) is a Maryland corporation that operates as a real estate investment trust ("REIT") for federal income tax purposes, and owns and operates commercial real estate properties. Columbia Property Trust conducts business primarily through Columbia Property Trust Operating Partnership, L.P. ("Columbia OP"), a Delaware limited partnership in which Columbia Property Trust is the general partner and majority owner (97.3%). Columbia Property Trust acquires, develops, redevelops, owns, leases, and operates real properties directly, through wholly owned subsidiaries, or through joint ventures. Unless otherwise noted herein, references to Columbia Property Trust, the "Company," "we," "us," or "our" herein shall include Columbia Property Trust and all subsidiaries of Columbia Property Trust, direct and indirect. As of March 31, 2021, Columbia Property Trust owned 15 operating properties and four properties under development or redevelopment, of which 10 were wholly owned and nine were owned through joint ventures, located in New York, San Francisco, Washington, D.C., and Boston. As of March 31, 2021, these operating properties contained 6.2 million rentable square feet and were approximately 94.0% leased. Columbia Property Trust also provides asset and property management services for 8.0 million square feet of office space located primarily in New York, Washington, D.C., and Boston.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements of Columbia Property Trust have been prepared in accordance with the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by U.S. generally accepted accounting principles ("GAAP") for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair and consistent presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year's results. For additional information on Columbia Property Trust's unconsolidated joint ventures, which are accounted for using the equity method of accounting, see Note 4, Unconsolidated Joint Ventures . Columbia Property Trust's consolidated financial statements include the accounts of Columbia Property Trust, Columbia OP, and any variable-interest entity in which Columbia Property Trust or Columbia OP is deemed the primary beneficiary. With respect to entities that are not variable interest entities, Columbia Property Trust's consolidated financial statements also include the accounts of any entity in which Columbia Property Trust, Columbia OP, or their subsidiaries own a controlling financial interest and any limited partnership in which Columbia Property Trust, Columbia OP, or their subsidiaries own a controlling general partnership interest. All intercompany balances and transactions have been eliminated in consolidation. For further information, refer to the financial statements and footnotes included in Columbia Property Trust's Annual Report on Form 10-K for the year ended December 31, 2020 (the "2020 Form 10-K"). Fair Value Measurements Columbia Property Trust estimates the fair value of its assets and liabilities (where currently required under GAAP) consistent with the provisions of Accounting Standard Codification 820, Fair Value Measurements ("ASC 820"). Under this standard, fair value is defined as the price that would be received upon sale of an asset or paid upon transfer of a liability in an orderly transaction between market participants at the measurement date, under current market conditions. While various techniques and assumptions can be used to estimate fair value depending on the nature of the asset or liability, the accounting standard for fair value measurements and disclosures provides the following fair value technique parameters and hierarchy, depending upon availability: Level 1 – Assets or liabilities for which the identical term is traded on an active exchange, such as publicly traded instruments or futures contracts. Level 2 – Assets or liabilities valued based on observable market data for similar instruments. Level 3 – Assets or liabilities for which significant valuation assumptions are not readily observable in the market. Such assets or liabilities are valued based on the best available data, some of which may be internally developed. Significant assumptions may include risk premiums that a market participant would consider. Real Estate Assets Columbia Property Trust is required to make subjective assessments as to the useful lives of its depreciable assets. To determine the appropriate useful life of an asset, Columbia Property Trust considers the period of future benefit of the asset. These assessments have a direct impact on net income. The estimated useful lives of its assets by class are as follows: Buildings 40 years Building and site improvements 5-25 years Tenant improvements Shorter of economic life or lease term Intangible lease assets Lease term With respect to development and redevelopment projects, Columbia Property Trust capitalizes construction costs, including hard and soft costs, operating costs and interest expense, as applicable. Interest expense is capitalized on development, redevelopment, and improvement projects funded directly and through its interest in unconsolidated joint ventures. During the three months ended March 31, 2021 and 2020, $2.8 million and $2.6 million, respectively, of interest was capitalized to construction in progress; and during the three months ended March 31, 2021 and 2020, $0.8 million and $0.4 million, respectively, of interest was capitalized to investments in unconsolidated joint ventures. See Note 5., Line of Credit and Notes Payable , for additional information. Assets Held for Sale Columbia Property Trust classifies properties as held for sale according to Accounting Standard Codification 360, Accounting for the Impairment or Disposal of Long-Lived Assets ("ASC 360"). According to ASC 360, properties having separately identifiable operations and cash flows are considered held for sale when all of the following criteria are met: • Management, having the authority to approve the action, commits to a plan to sell the property. • The property is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such property. • An active program to locate a buyer and other actions required to complete the plan to sell the property have been initiated. • The property is being actively marketed for sale at a price that is reasonable in relation to its current fair value. • Actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. • The sale of the property is probable (i.e., typically subject to a binding sale contract with a non-refundable deposit), and transfer of the property is expected to qualify for recognition as a completed sale within one year. As of March 31, 2021 and December 31, 2020, none of Columbia's properties met the criteria to be classified as held for sale in the accompanying consolidated balance sheets. Evaluating the Recoverability of Real Estate Assets Columbia Property Trust continually monitors events and changes in circumstances that could indicate that the net carrying amounts of its real estate and related intangible assets and liabilities, of both operating properties and properties under development or redevelopment, may not be recoverable. When indicators of potential impairment are present that suggest that the net carrying amounts of real estate assets and related intangible assets and liabilities may not be recoverable, Columbia Property Trust assesses the recoverability of these net assets by determining whether the respective carrying values will be recovered through the estimated undiscounted future cash flows expected from the use of the net assets and their eventual disposition. In the event that such expected undiscounted future cash flows do not exceed the carrying values, Columbia Property Trust adjusts the carrying values of the real estate assets and related intangible assets and liabilities to the estimated fair values, pursuant to the property, plant, and equipment accounting standard for the impairment or disposal of long-lived assets, and recognizes an impairment loss. At such time that a property is required to be classified as held for sale, its net carrying amount is adjusted to the lower of its depreciated book value or its estimated fair value, less costs to sell, and depreciation is no longer recognized. Estimated fair values are calculated based on the following hierarchy of information: (i) recently quoted market prices, (ii) market prices for comparable properties, or (iii) the present value of future cash flows, including estimated residual value. Projections of expected future operating cash flows require that Columbia Property Trust estimate future market rental income amounts subsequent to the expiration of current lease agreements, property operating expenses, the number of months it takes to re-lease the property, and the number of years the property is held for investment, among other factors. Due to the inherent subjectivity of the assumptions used to project future cash flows, estimated fair values may differ from the values that would be realized in market transactions. Certain of Columbia Property Trust's assets may be carried at an amount that exceeds that which could be realized in a current disposition transaction. Columbia Property Trust has determined that the carrying values of its real estate assets and related intangible assets are recoverable as of March 31, 2021. Intangible Assets and Liabilities Arising From In-Place Leases Where Columbia Property Trust Is the Lessor Upon the acquisition of real properties, Columbia Property Trust allocates the purchase price of the properties to tangible assets, consisting of land, building, site improvements, and identified intangible assets and liabilities, including the value of in-place leases, based in each case on Columbia Property Trust's estimate of their fair values in accordance with ASC 820 (see "Fair Value Measurements" section above for additional detail). As of March 31, 2021 and December 31, 2020, Columbia Property Trust had the following intangible assets and liabilities, arising from in-place leases, excluding amounts held for sale, if applicable (in thousands): Intangible Lease Assets Intangible Intangible Above-Market Absorption March 31, 2021 Gross $ 2,480 $ 99,153 $ 55,814 $ 21,281 Accumulated Amortization (1,416) (56,554) (35,662) (7,582) Net $ 1,064 $ 42,599 $ 20,152 $ 13,699 December 31, 2020 Gross $ 2,480 $ 101,542 $ 56,612 $ 23,287 Accumulated Amortization (1,374) (56,573) (35,161) (8,867) Net $ 1,106 $ 44,969 $ 21,451 $ 14,420 Amortization of Intangible Assets and Liabilities Arising From In-Place Leases For the three months ended March 31, 2021 and 2020, Columbia Property Trust recognized the following amortization of intangible lease assets and liabilities (in thousands): Intangible Lease Assets Intangible Intangible Above-Market Absorption For the Three Months Ended March 31, 2021 $ 42 $ 2,369 $ 1,299 $ 722 For the Three Months Ended March 31, 2020 $ 43 $ 3,700 $ 1,586 $ 1,596 The net intangible assets and liabilities remaining as of March 31, 2021 will be amortized as follows, excluding amounts held for sale, if applicable (in thousands): Intangible Lease Assets Intangible Intangible Above-Market Absorption For the remainder of 2021 $ 129 $ 6,594 $ 3,111 $ 2,080 For the years ending December 31: 2022 172 7,620 3,335 2,571 2023 172 6,138 2,810 1,995 2024 172 5,333 2,500 1,748 2025 172 3,943 1,849 1,182 2026 109 2,832 1,321 964 Thereafter 138 10,139 5,226 3,159 $ 1,064 $ 42,599 $ 20,152 $ 13,699 Investments in Unconsolidated Joint Ventures Columbia Property Trust uses the equity method to account for investments that are not wholly owned and: (i) are considered variable interest entities where the Company is not the primary beneficiary, or (ii) in which the Company, along with its co-owners, possesses substantive participation rights, including management selection and termination, and the approval of significant capital and operating decisions. Under the equity method, investments in unconsolidated joint ventures are recorded at cost and adjusted for cash contributions and distributions, and allocations of income or loss. Investments in Real Estate Funds Columbia Property Trust holds general partnership interests and limited partnership interests in three real estate funds: Normandy Real Estate Fund III, LP; Normandy Real Estate Fund IV, LP; and Normandy Opportunity Zone Fund, LP (collectively, the "Real Estate Funds"). The Company owns minimal economic interests in the Real Estate Funds (ranging from 2.0% to 2.5%). Significant decision rights are shared between the general partners and limited partners and a general partner can be removed with a majority vote from the limited partners. As a result, Columbia Property Trust accounts for its investments in the Real Estate Funds using the equity method. The Real Estate Funds are subject to the rules of the AICPA Investment Company Guide; as a result, GAAP requires the Company to record its investments in the Real Estate Funds at their respective estimated fair market values. The Company determines the Real Estate Funds' estimated net asset values per share using a discounted cash flow model, which is considered a Level 3 valuation technique (see "Fair Value Measurements " section above). As of March 31, 2021 and December 31, 2020, investments in the Real Estate Funds of approximately $4.2 million and $4.3 million, respectively, are included in prepaid expenses and other assets on the accompanying consolidated balance sheet. For the three months ended March 31, 2021 and 2020, Columbia Property Trust recognized unrealized losses on its investments in Real Estate Funds of approximately $0.2 million, which are recorded as other income (loss) in the accompanying consolidated statements of operations. Columbia Property Trust has entered into agreements to provide acquisition, disposition, investment management, property management, leasing, and other services to the properties in which the Real Estate Funds own interests. See Note 12, Non-Lease Revenues , for more details. From time to time, Columbia Property Trust may be required to make additional capital contributions to the Real Estate Funds. See Note 7, Commitments and Contingencies , for more details . Tenant Receivables Tenant receivables consist of rental and reimbursement billings due from tenants. Tenant receivables are recorded at the original amount earned, which approximates fair value. Management assesses the realizability of tenant receivables on an ongoing basis. When the collectability of tenant receivables is not considered probable, the receivable is written down against lease revenues. During the three months ended March 31, 2021 and 2020, $1,340,000 and $8,000, respectively, of tenant receivables were written down against lease revenues. Straight-Line Rent Receivable Straight-line rent receivable reflects the amount of cumulative adjustments necessary to present rental income on a straight-line basis. Columbia Property Trust recognizes rental revenues on a straight-line basis, ratably over the term of each lease; however, leases often provide for payment terms that differ from the revenue recognized. When the amount of cash billed is less than the amount of revenue recognized, typically early in the lease, straight-line rent receivable is recorded for the difference. The receivable is depleted during periods later in the lease when the amount of cash paid by the tenant is greater than the amount of revenue recognized. When the collection of future rental billings is not considered probable, tenants are moved to "cash basis billings," at which point the corresponding straight-line rent receivable is written-down against lease revenues, and future revenues are recognized upon receipt of payment. During the three months ended March 31, 2021, approximately $0.2 million of straight-line rent receivables were written down against lease revenues. Interest Rate Swap Agreements Columbia Property Trust enters into interest rate swap contracts to mitigate its interest rate risk on the related financial instruments. Columbia Property Trust does not enter into derivative or interest rate swap transactions for speculative purposes and currently does not have any derivatives that are not designated as hedges; however, certain of its derivatives may, at times, not qualify for hedge accounting treatment. Columbia Property Trust records the fair value of its interest rate swaps on its consolidated balance sheet either as prepaid expenses and other assets or as accounts payable, accrued expenses, and accrued capital expenditures. Changes in the fair value of interest rate swaps that are designated as cash flow hedges are recorded as other comprehensive income (loss). Changes in the fair value of interest rate swaps that do not qualify for hedge accounting treatment are recorded as gain or loss on interest rate swaps. Amounts received or paid under interest rate swap agreements are recorded as interest expense for contracts that qualify for hedge accounting treatment and as gain or loss on interest rate swaps for contracts that do not qualify for hedge accounting treatment. As of March 31, 2021, Columbia Property Trust has two interest rate swaps with an aggregate notional value of $450.0 million. The following tables provide additional information related to Columbia Property Trust's interest rate swaps (in thousands): Estimated Fair Value as of Instrument Type Balance Sheet Classification March 31, December 31, Derivatives Designated as Hedging Instruments: Interest rate contracts Accounts payable $ 14,096 $ 18,720 Columbia Property Trust applied the provisions of ASC 820 in recording its interest rate swaps at fair value. The fair values of the interest rate swaps, classified under Level 2, were determined using a third-party proprietary model that is based on prevailing market data for contracts with matching durations, current and anticipated London Interbank Offered Rate ("LIBOR") information, and reasonable estimates about relevant future market conditions. Columbia Property Trust has determined that the fair value, as determined by the third party, is reasonable. Three Months Ended 2021 2020 Market value adjustment to interest rate swaps designated as hedging instruments and included in other comprehensive income (loss) $ 4,624 $ (19,993) During the periods presented, no hedge ineffectiveness was required to be recognized into earnings on the interest rate swaps that qualified for hedge accounting treatment. Noncontrolling Interests Noncontrolling interests represent the portion of equity in consolidated entities that is owned by third parties. Noncontrolling interests are adjusted for cash contributions and distributions, and for earnings. Such earnings are allocated between the Company and noncontrolling interests using the hypothetical liquidation at book value method pursuant to the terms of the respective ownership agreements, and are reflected as net income (loss) attributable to noncontrolling interests in the accompanying consolidated statements of operations. Strategic Review Costs In the first quarter of 2021, the Company incurred approximately $2.4 million of strategic review and proxy contest costs related to a proxy contest, which was subsequently withdrawn in late April, and the ongoing strategic alternative review process. These costs are expensed as incurred. Income Taxes Columbia Property Trust has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the "Code") and has operated as such beginning with its taxable year ended December 31, 2003. To qualify as a REIT, the Company must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its REIT taxable income, as defined by the Code, to its stockholders. To the extent that Columbia Property Trust satisfies the distribution requirement but distributes less than 100% of its REIT taxable income, the Company would be subject to federal and state corporate income tax on the undistributed income. Generally, the Company does not incur federal income taxes, other than as described in the following paragraph, because its stockholder distributions typically exceed its taxable income due to noncash expenses such as depreciation. Columbia Property Trust is, however, subject to certain state and local taxes related to the operations of properties in certain locations, which have been provided for in the accompanying consolidated financial statements. Columbia Property Trust TRS, LLC; Columbia KCP TRS, LLC; Columbia Development TRS 13, LLC; and Columbia Development TRS 87, LLC (collectively, the "TRS Entities") are subsidiaries of the Company and are organized as Delaware limited liability companies. The TRS Entities, among other things, provide services related to asset and property management, construction and development, and other tenant services that Columbia Property Trust, as a REIT, cannot otherwise provide. The Company has elected to treat the TRS Entities as taxable REIT subsidiaries. Columbia Property Trust may perform certain additional, noncustomary services for tenants of its buildings through the TRS Entities; however, earnings of a TRS entity are subject to federal and state income taxes. In addition, for the Company to continue to qualify as a REIT, Columbia Property Trust must limit its investments in taxable REIT subsidiaries to 20% of the value of the total assets. The TRS Entities' deferred tax assets and liabilities represent temporary differences between the financial reporting basis and the tax basis of assets and liabilities based on the enacted rates expected to be in effect when the temporary differences reverse. If applicable, the Company records interest and penalties related to uncertain tax positions as general and administrative expense in the accompanying consolidated statements of operations. Reclassification Certain prior-period amounts on the consolidated statement of cash flows have been reclassified to conform with the current-period presentation. With respect to adjustments to reconcile net income to cash provided by operating activities, lease revenues reserved for doubtful accounts – tenant receivables includes amounts previously reported in decrease (increase) in tenant receivables, net. Recent Accounting Pronouncements Accounting Standard Update 2021-01, Reference Rate Reform ("ASC 2021-01"), which was issued on and effective as of January 7, 2021, refines the scope of ASC 848, Reference Rate Reform ("ASC 848"), which was codified last year to address the accounting and disclosure impacts of reference rate reform and the anticipated discontinuance of LIBOR. Columbia Property Trust has matched LIBOR-based debt with LIBOR-based interest rate swaps, and has elected to apply the practical expedients provided for in ASC 848 related to (i) probability and (ii) the assessment of the effectiveness for future LIBOR-indexed cash flows, which assume that the debt instrument will use the same index rate as its corresponding interest rate swap, once a new reference rate is established to replace LIBOR. Application of these expedients preserves the effectiveness of the Company's interest rate swaps as cash flow hedges in the event that its debt and interest rate swaps are not amended concurrently to reflect a new reference rate. ASC 2021-01 allows for entities to either apply the practical expedient as Columbia has elected to do, or change its effectiveness approach to a quantitative model as provided for in existing guidance. Columbia Property Trust continues to evaluate the impact of the guidance and may apply other elections as additional reference rate changes occur. ASC 848 and ASU 2021-01 may be

Transactions

Transactions	3 Months Ended
	Mar. 31, 2021
Real Estate [Abstract]
Transactions	Transactions Terminal Warehouse Joint Venture Investment On March 13, 2020, Columbia Property Trust acquired a one-third general partnership interest and limited partnership interests, totaling an 8.65% economic interest, in Terminal Warehouse for $40.0 million. Terminal Warehouse is a 1.2-million-square-foot property located in West Chelsea, New York, that will be fully redeveloped into mixed-use retail and office space (the "Terminal Warehouse Joint Venture"). The Terminal Warehouse Joint Venture has a two-year, interest-only acquisition loan with a total capacity of $650.0 million, and an outstanding balance of $645.5 million as of March 31, 2021. After executing an extension in April 2021, the loan matures on May 24, 2021, with two extension options for a total possible extension period of eight Unconsolidated Joint Ventures , and Note 12, Non-Lease Revenues , for more detail. Real Estate Dispositions During 2020, Columbia Property Trust sold the following properties. Additional information for certain of the disposition transactions is provided below the table. There have been no real estate dispositions in 2021 to date. Property Location Date % Sold Sales Price (1) (in thousands) Gain (loss) on Sale 2020 221 Main Street San Francisco, CA October 8, 2020 45 % $ 180,000 $ 175,271 Pasadena Corporate Park Los Angeles, CA March 31, 2020 100 % $ 78,000 $ (67) Cranberry Woods Drive Pittsburgh, PA January 16, 2020 100 % $ 180,000 $ 13,428 (1) Exclusive of transaction costs and price adjustments. 221 Main Street – Partial Sale On October 8, 2020, Columbia Property Trust contributed 221 Main Street to a joint venture and simultaneously sold a 45.0% interest in this joint venture (the "221 Main Street Joint Venture") for a gross sales price of $180.0 million, exclusive of transaction costs, resulting in a gain on sale of $175.3 million in the fourth quarter of 2020. Following this transaction, Columbia Property Trust owns a 55.0% interest in the 221 Main Street Joint Venture. The proceeds from this transaction were used to pay down the Revolving Credit Facility, as described in Note 5, Line of Credit and Notes Payable , during the fourth quarter of 2020. Pasadena Corporate Park On March 31, 2020, Columbia Property Trust closed on the sale of Pasadena Corporate Park for a gross sales price of $78.0 million, exclusive of transaction costs, resulting in a loss on sale of $67,000. Columbia Property Trust recognized an impairment loss of $20.6 million related to this property in the fourth quarter of 2019. At the time of sale, the proceeds from this transaction were held in cash and cash equivalents. Cranberry Woods Drive On January 16, 2020, Columbia Property Trust closed on the sale of Cranberry Woods Drive for a gross sales price of $180.0 million, exclusive of transaction costs, resulting in a gain on sale of $13.4 million. The proceeds from this transaction were used to pay down the Revolving Credit Facility, as described in Note 5, Line of Credit and Notes Payable . Normandy Acquisition On January 24, 2020, Columbia Property Trust acquired Normandy Real Estate Management, LLC ("Normandy"), a developer, operator, and investment manager of office and mixed-use assets with a focus on assets in New York, Boston, and Washington, D.C. (the "Normandy Acquisition"). As a result of the Normandy Acquisition, the Company acquired an operating platform, interests in the Real Estate Funds, and contracts to earn fees for providing management services to properties affiliated with the Real Estate Funds (see Note 12, Non-Lease Revenues , for details). The purchase price, exclusive of adjustments and transaction costs, is comprised of two components: (i) an approximately $14.0 million cash payment, and (ii) the issuance of 3,264,151 Series A Convertible, Perpetual Preferred Units of Columbia OP with a liquidation preference of $26.50 per unit (the "Preferred OP Units"). The Preferred OP Units are convertible for common units of Columbia OP, which are exchangeable into shares of Columbia Property Trust's common stock, subject to certain terms and conditions. As of the closing date of the acquisition, the Preferred OP Units had an estimated fair value of $24.43 per unit. The fair value of the Preferred OP Units was determined using a lattice valuation model, utilizing significant unobservable inputs (Level 3 under the fair value hierarchy described in Note 2, Summary of Significant Accounting Policies ). The initial purchase consideration was allocated as follows (in thousands): January 24, 2020 Goodwill (1) $ 63,806 Prepaid expenses and other assets (2) 7,670 Cash 1,260 Operating lease assets 934 Investments in unconsolidated joint ventures (3) 419 Accounts payable, accrued expenses, and accrued capital expenditures (2,881) Operating lease liabilities (934) Deferred income (77) Total initial purchase consideration $ 70,197 (1) In the fourth quarter of 2020, in connection with Columbia's annual assessment of the recoverability of goodwill, the Company wrote off this balance by recording an impairment loss of $63.8 million. (2) Prepaid expenses and other assets includes $3.7 million of investments in Real Estate Funds, as described in Note 2, Summary of Significant Accounting Policies . (3) Reflects interests in five unconsolidated joint ventures that earn fees for providing management services to properties affiliated with the Real Estate Funds.

Unconsolidated Joint Ventures

Unconsolidated Joint Ventures	3 Months Ended
	Mar. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Unconsolidated Joint Ventures	Unconsolidated Joint Ventures As of March 31, 2021 and December 31, 2020, Columbia Property Trust owned interests in the following properties through joint ventures, which are accounted for using the equity method of accounting (in thousands): Carrying Value of Investment (1) Joint Venture Property Name Geographic Market Ownership Interest March 31, 2021 December 31, 2020 University Circle Joint Venture University Circle San Francisco 55.00 % $ 275,867 $ 276,574 333 Market Street Joint Venture 333 Market Street San Francisco 55.00 % 264,483 265,673 1800 M Street Joint Venture 1800 M Street Washington, D.C. 55.00 % 225,888 227,847 221 Main Street Joint Venture 221 Main Street San Francisco, CA 55.00 % 217,057 219,078 114 Fifth Avenue Joint Venture 114 Fifth Avenue New York 49.50 % 75,367 74,273 Market Square Joint Venture Market Square Washington, D.C. 51.00 % 133,726 134,747 799 Broadway Joint Venture (2) 799 Broadway New York, NY 49.70 % 55,888 53,248 Terminal Warehouse Joint Venture (2) Terminal Warehouse New York, NY 8.65 % 46,571 43,771 Real Estate Services Joint Ventures (3) n/a (3) n/a (3) Various (3) 572 589 $ 1,295,419 $ 1,295,800 (1) Includes basis differences. There are aggregate net differences between the historical costs recorded at the joint venture level, and Columbia Property Trust's investments in unconsolidated joint ventures of $382.1 million and $383.5 million as of March 31, 2021 and December 31, 2020, respectively. Such basis differences result from the timing of each partner's joint venture interest acquisition; and formation costs incurred by Columbia Property Trust. Basis differences are amortized to income (loss) from unconsolidated joint ventures over the lives of the underlying assets or liabilities. (2) Columbia Property Trust capitalized interest on its investment in the 799 Broadway Joint Venture and the Terminal Warehouse Joint Venture: $0.8 million and $0.3 million during the three months ended March 31, 2021 and 2020, respectively. (3) Columbia Property Trust owns the following interests in five unconsolidated joint ventures that earn fees for providing real estate management services to properties affiliated with the Real Estate Funds (the "Real Estate Services Joint Ventures"): L&L Normandy Terminal Asset Manager, LLC (67%); L&L Normandy Terminal Development Manager, LLC (50%); L&L Normandy Terminal Property Manager (50%) (collectively, the "Terminal Services Joint Ventures"); WNK Maiden Management (50%); and Maple AB Services, LLC (55%). The Terminal Services Joint Ventures earn fees from providing services to the Terminal Warehouse Joint Venture. Columbia Property Trust has determined that two of its unconsolidated joint ventures are variable interest entities and the Company is not the primary beneficiary. Therefore, the Company uses the equity method of accounting to record its investment in these joint ventures. For the remaining joint ventures, Columbia Property Trust and its partners have substantive participation rights in the unconsolidated joint ventures, including management selection and termination, and the approval of operating and capital decisions. As such, Columbia Property Trust also uses the equity method of accounting to record its investment in these joint ventures. Under the equity method, investments in unconsolidated joint ventures are recorded at cost and adjusted for cash contributions and distributions, and allocations of income or loss. Columbia Property Trust evaluates the recoverability of its investments in unconsolidated joint ventures in accordance with accounting standards for equity investments by first reviewing the investment for any indicators of impairment. If indicators are present, Columbia Property Trust estimates the fair value of the investment. If the carrying value of the investment exceeds the estimated fair value, management makes an assessment of whether the deficit is "temporary" or "other-than-temporary," and if "other-than-temporary," reduces the carrying value to reflect the estimated fair value by recording an impairment loss. In making this assessment, management considers the following: (1) the length of time and the extent to which fair value has been less than cost and (2) Columbia Property Trust's intent and ability to retain its interest long enough for a recovery in market value. Based on the analysis described above, Columbia Property Trust has determined that none of its investments in joint ventures are impaired as of March 31, 2021. Condensed Combined Financial Information Summarized balance sheet information for each of the unconsolidated joint ventures is as follows (in thousands): Total Assets Total Debt Total Equity (1) March 31, December 31, 2020 March 31, December 31, 2020 March 31, December 31, 2020 University Circle Joint Venture $ 214,280 $ 213,045 $ — $ — $ 208,653 $ 208,541 333 Market Street Joint Venture 354,835 357,370 — — 341,676 344,103 1800 M Street Joint Venture 421,219 427,602 — — 408,417 411,957 221 Main Street Joint Venture 230,231 229,745 — — 224,523 224,732 114 Fifth Avenue Joint Venture 464,030 462,319 — — 104,567 101,952 Market Square Joint Venture 568,545 577,095 324,881 (2) 324,868 235,187 237,778 799 Broadway Joint Venture 255,670 246,456 144,116 (3) 138,930 103,249 99,000 Terminal Warehouse Joint Venture 1,079,057 1,045,852 645,081 (4) 643,819 406,725 380,277 Real Estate Services Joint Ventures 1,581 1,754 — — 977 1,104 $ 3,589,448 $ 3,561,238 $ 1,114,078 $ 1,107,617 $ 2,033,974 $ 2,009,444 (1) Excludes basis differences (see footnote (1) to the Carrying Value of Investment table above), which are amortized to income (loss) from unconsolidated joint ventures over the lives of the underlying assets or liabilities. (2) The Market Square Joint Venture has a $325.0 million mortgage note. The Market Square mortgage note bears interest at 5.07% and matures on July 1, 2023. (3) Reflects $145.1 million outstanding, net of $1.0 million of net unamortized deferred financing costs, on the 799 Broadway construction loan. The 799 Broadway construction loan is being used to finance a portion of the 799 Broadway development project, has total capacity of $187.0 million, and bears interest at LIBOR plus a spread of 425 basis points, with a LIBOR floor of 1.00% and capped of 4.00% (the "Construction Loan"). A portion of the monthly interest payments accrue into the balance of the loan. The Construction Loan matures on October 9, 2021, with two one-year extension options. For a discussion of Columbia Property Trust's equity guaranty related to the Construction Loan, see Note 7, Commitments and Contingencies . (4) Reflects $645.5 million outstanding, net of $0.4 million of net unamortized deferred financing costs, on the Terminal Warehouse acquisition loan. The Terminal Warehouse Joint Venture has an interest-only acquisition loan with a total capacity of $650.0 million. The Terminal Warehouse acquisition loan bears interest at LIBOR plus a spread of 340 basis points, with a LIBOR floor of 2.28% and cap of 3.50%, and matures on May 24, 2021, with two extension options for a total possible extension period of eight Summarized income statement information for the unconsolidated joint ventures for the three months ended March 31, 2021 and 2020 is as follows (in thousands): Total Revenues Net Income (Loss) Columbia Property Trust's Share of Net Income (Loss) (1) 2021 2020 2021 2020 2021 2020 University Circle Joint Venture $ 10,305 $ 10,924 $ 5,112 $ 5,715 $ 2,811 $ 3,144 333 Market Street Joint Venture 7,135 7,067 3,672 3,705 2,020 2,037 1800 M Street Joint Venture 9,631 9,937 1,463 1,752 805 964 221 Main Street Joint Venture 7,982 — 2,583 — 1,420 — 114 Fifth Avenue Joint Venture 10,735 10,428 6,865 (2,653) 3,398 (1,314) Market Square Joint Venture 12,597 12,690 (2,586) (1,994) (1,319) (1,017) 799 Broadway Joint Venture — — (40) (32) (20) (16) Terminal Warehouse Joint Venture 2,173 2,307 (2,152) (3,741) (186) (324) Real Estate Services Joint Ventures 1,889 1,875 962 938 565 341 $ 62,447 $ 55,228 $ 15,879 $ 3,690 $ 9,494 $ 3,815 (1) Excludes amortization of basis differences (see footnote to (1) the Carrying Value of Investment table above), which are recorded as income (loss) from unconsolidated joint ventures in the accompanying consolidated statements of operations. Management Fees Columbia Property Trust provides property and asset management services to certain of its joint ventures. Under these agreements, Columbia Property Trust oversees the day-to-day operations of these joint ventures and their properties, including property management, property accounting, leasing, construction management and other administrative services. During the three months ended March 31, 2021 and 2020, Columbia Property Trust earned the following fees from its unconsolidated joint ventures (in thousands): Three Months Ended 2021 2020 University Circle Joint Venture $ 587 $ 587 333 Market Street Joint Venture 209 214 1800 M Street Joint Venture 562 555 221 Main Street Joint Venture 471 — Market Square Joint Venture 605 574 799 Broadway Joint Venture — 223 $ 2,434 $ 2,153 For the three months ended March 31, 2021 and 2020, Columbia Property Trust earned reimbursement income for management fee administration costs of $1.4 million and $1.3 million, respectively, which is included in management fee revenues. Asset and property management fees of $0.5 million and $0.4 million were due to Columbia Property Trust from the joint ventures and are included in prepaid expenses and other assets on the accompanying consolidated balance sheets as of March 31, 2021 and December 31, 2020, respectively.

Line of Credit and Notes Payabl

Line of Credit and Notes Payable	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Line of Credit and Notes Payable	Line of Credit and Notes Payable As of March 31, 2021 and December 31, 2020, Columbia Property Trust had the following line of credit and notes payable indebtedness (excluding bonds payable; see Note 6, Bonds Payable ) (in thousands): Facility March 31, December 31, $300 Million Term Loan $ 300,000 $ 300,000 $150 Million Term Loan 150,000 150,000 Revolving Credit Facility 124,000 110,000 Less: Deferred financing costs related to term loans and notes payable, net of accumulated amortization (1,316) (1,470) $ 572,684 $ 558,530 Columbia Property Trust's amended and restated credit and term loan agreement (the "Credit Agreement") provides for (i) a $650.0 million unsecured revolving credit facility (the "Revolving Credit Facility"), with an initial term ending January 31, 2023 and two six-month extension options (for a total possible extension option of one year to January 31, 2024), subject to the payment of certain fees and the satisfaction of certain other conditions, and (ii) a $300.0 million unsecured term loan, with a term ending January 31, 2024 (the "$300 Million Term Loan"). At Columbia Property Trust's option, borrowings under the Credit Agreement bear interest at either (i) the alternate base rate plus an applicable margin based on five stated pricing levels ranging from 0.00% to 0.45% for the Revolving Credit Facility and 0.00% to 0.65% for the $300 Million Term Loan, or (ii) the LIBOR rate, as defined in the credit agreement, plus an applicable margin based on five stated pricing levels ranging from 0.775% to 1.45% for the Revolving Credit Facility and 0.85% to 1.65% for the $300 Million Term Loan, in each case based on Columbia Property Trust's credit rating. The interest rate on the $300 Million Term Loan has been effectively fixed at 2.55% with an interest rate swap agreement, which is designated as a cash flow hedge. Columbia Property Trust's $150.0 million unsecured term loan matures in July 2022 (the "$150 Million Term Loan") and bears interest, at the Company's option, at either (i) LIBOR, plus an applicable margin ranging from 0.90% to 1.75% for LIBOR loans, or (ii) alternative base rate, plus an applicable margin ranging from 0.00% to 0.75% for base rate loans. The interest rate on the $150 Million Term Loan is effectively fixed with an interest rate swap agreement, which is designated as a cash flow hedge. Based on the terms of the interest rate swap and the Company's current credit rating, the interest rate on the $150 Million Term Loan is effectively fixed at 3.07%, which is designated as a cash flow hedge. Fair Value of Debt The estimated fair value of Columbia Property Trust's line of credit and notes payable as of March 31, 2021 and December 31, 2020, was approximately $578.0 million and $564.6 million, respectively. The related carrying value of the line of credit and notes payable as of March 31, 2021 and December 31, 2020, was $574.0 million and $560.0 million, respectively. Columbia Property Trust estimated the fair value of its term loans and the Revolving Credit Facility by obtaining estimates for similar facilities from multiple market participants as of the respective reporting dates. Therefore, the fair values determined are considered to be based on observable market data for similar instruments (Level 2). Interest Paid and Capitalized During the three months ended March 31, 2021 and 2020, Columbia Property Trust made interest payments of approximately $3.7 million and $5.0 million, respectively. Columbia Property Trust capitalizes interest on development, redevelopment, and improvement projects funded directly and through its interest in unconsolidated joint ventures, using the weighted-average interest rate of its consolidated borrowings for the period. During the three months ended March 31, 2021, Columbia Property Trust capitalized interest of $3.6 million, $2.8 million of which was capitalized to construction in progress, and $0.8 million of which was capitalized to investments in unconsolidated joint ventures. During the three months ended March 31, 2020, Columbia Property Trust capitalized interest of $3.0 million, $2.6 million of which was capitalized to construction in progress, and $0.4 million of which was capitalized to investments in unconsolidated joint ventures. For the three months ended March 31, 2021, the weighted average interest rate on Columbia Property Trust's consolidated outstanding borrowings was 3.23%. Debt Covenants As of March 31, 2021, Columbia Property Trust was in compliance with all of its debt covenants on its term loans and the Revolving Credit Facility.

Bonds Payable

Bonds Payable	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Bonds Payable	Bonds Payable Columbia Property Trust has two series of bonds outstanding as of March 31, 2021 and December 31, 2020: $350.0 million of 10-year, unsecured 3.650% senior notes issued at 99.626% of their face value (the "2026 Bonds Payable"); and $350.0 million of 10-year, unsecured 4.150% senior notes issued at 99.859% of their face value (the "2025 Bonds Payable"), (collectively, the "Bonds Payable"). Both series of bonds require semi-annual interest payments. The principal amount of the 2026 Bonds Payable is due and payable on August 15, 2026, and the principal amount of the 2025 Bonds Payable is due and payable on April 1, 2025. The Bonds Payable were issued by Columbia OP and are fully and unconditionally guaranteed by Columbia Property Trust, Inc. Interest payments of $6.4 million were made on the Bonds Payable during both the three months ended March 31, 2021 and 2020. Columbia Property Trust is subject to substantially similar covenants under the 2026 Bonds Payable and the 2025 Bonds Payable. As of March 31, 2021, Columbia Property Trust was in compliance with the restrictive financial covenants on the 2026 Bonds Payable and the 2025 Bonds Payable. As of March 31, 2021 and December 31, 2020, the estimated fair value of the Bonds Payable was approximately $755.1 million and $738.2 million, respectively, and the related carrying value, net of discounts, as of March 31, 2021 and December 31, 2020 was $699.1 million. The fair value of the Bonds Payable was estimated based on a discounted cash flow analysis, using observable market data for its bonds payable and similar instruments (Level 2). The discounted cash flow method of assessing fair value results in a general approximation of value, which may differ from the price that could be achieved in a market transaction.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments Under Existing Lease Agreements Certain lease agreements include tenant allowances that, at the option of the tenant, may obligate Columbia Property Trust to expend capital to improve an existing property, or to provide other expenditures for the benefit of the tenant. As of March 31, 2021, the Company is required to fund an additional $42.5 million for construction and tenant improvement allowances related to a vertical expansion project at 80 M Street in Washington, D.C., and $25.2 million related to lobby and tenant improvement allowances for the Pershing lease at 95 Columbus in Jersey City, New Jersey. As of March 31, 2021, accruals have not been recorded for these amounts, as such obligations are recorded as incurred. Commitments Under Joint Venture Agreements Columbia Property Trust's joint venture agreements, including those that are in place with joint ventures that are developing or redeveloping properties, provide for capital contributions to be made to the joint ventures by the joint venture partners. As of March 31, 2021, Columbia Property Trust holds nine properties through consolidated and unconsolidated joint ventures, including three that are under development or redevelopment. Capital contributions are payable when a capital call is made by the joint venture, and there are no unfunded capital calls as of March 31, 2021. As of March 31, 2021, the 799 Broadway Joint Venture has $145.1 million in outstanding borrowings on the Construction Loan, which matures on October 9, 2021. Pursuant to a joint and several guaranty agreement with the Construction Loan lender, Columbia Property Trust and its joint venture partner are required to make aggregate additional equity contributions to the joint venture based on the initial expected project costs, less the amount of equity contributions made to date. As of March 31, 2021, the remaining equity contribution requirement is $13.7 million, of which $6.8 million reflects Columbia Property Trust's allocated share. Equity contributions become payable by Columbia Property Trust to the joint venture when a capital call is received. As of March 31, 2021, no capital calls remain unpaid; therefore, no liability has been recorded related to this guaranty. Commitments Under Real Estate Fund Agreements Columbia Property Trust's Real Estate Fund investments require capital contributions from time to time. As of March 31, 2021, the Company had $3.8 million of unfunded capital contributions, which are callable for the life of the Real Estate Funds, through 2026. Such capital contributions are payable when a capital call is made by the Real Estate Funds, and there are no unfunded capital calls as of March 31, 2021. Litigation

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Common Stock Repurchase Program Columbia Property Trust's board of directors authorized a stock repurchase program to purchase up to an aggregate of $200.0 million of its common stock, from September 4, 2019 through September 4, 2021 (the "2019 Stock Repurchase Program"). No share repurchases were made during the three months ended March 31, 2021. As of March 31, 2021, $143.3 million remains available for repurchases under the 2019 Stock Repurchase Program. Common stock repurchases are charged against equity as incurred, and the repurchased shares are retired. Long-Term Incentive Compensation Columbia Property Trust maintains a stockholder-approved, long-term incentive plan (the "LTI Plan") that provides for grants of up to 4.8 million shares of stock to be made to certain employees and independent directors of Columbia Property Trust. Employee Awards Under the LTI Plan, Columbia Property Trust grants time-based stock awards and performance-based restricted stock unit awards to its employees. During the three months ended March 31, 2021, Columbia Property Trust granted 421,962 shares of stock awards (the "Time-Based Restricted Shares") to employees, which will vest ratably on each anniversary of the grant over the next four years. Also, during the three months ended March 31, 2021, Columbia Property Trust granted 429,977 of performance-based restricted stock units (the "Performance-Based RSUs"), of which 75% will vest at the conclusion of a three-year performance period, and the remaining 25% will vest one year later. The payout of the Performance-Based RSUs will be determined based on Columbia Property Trust's total stockholder return relative to the FTSE NAREIT Equity Office Index and is contingent upon meeting predetermined minimum performance levels. Below is a summary of the employee awards issued under the LTI Plan during the three months ended March 31, 2021: Time-Based Awards Performance-Based Awards Restricted Shares Weighted-Average Grant-Date Fair Value (1) RSUs Weighted-Average Grant-Date Fair Value (2) Unvested awards – beginning of period 497 $ 20.82 715 $ 18.51 Granted 422 $ 14.33 430 $ 12.39 Converted (3) 24 (24) Vested (4) (195) $ 21.32 (73) $ 20.66 Forfeited (2) $ 14.34 (1) $ 12.39 Unvested awards – end of period (5) 746 $ 15.75 1,047 $ 15.16 (1) Reflects the weighted-average, grant-date fair value using the market closing price on the date of the respective grants. (2) Reflects the weighted-average, grant-date fair value using a Monte Carlo valuation. (3) Reflects 25% of the 2018 3-year Performance-Based RSUs granted on January 1, 2018, which converted to Time-Based Restricted shares in January 2021 and will vest in January 2022. (4) With respect to the RSUs vesting this period, includes true-ups from the amount granted (based on target-level performance) to the respective amount paid (based on actual performance, as defined by the plan). (5) As of March 31, 2021, Columbia Property Trust expects approximately 712,000 of the 746,000 unvested restricted stock units to ultimately vest and approximately 1,000,000 of the 1,047,000 unvested Performance-Based RSUs to ultimately vest, assuming a weighted-average forfeiture rate of 4.5%, which was determined based on historical forfeiture rates. Director Stock Grants Columbia Property Trust grants equity retainers to its directors under the LTI Plan. Such grants are made annually for the following year and vest immediately. During the three months ended March 31, 2021 and 2020, Columbia Property Trust made the following equity retainer grants: Date of Grant Shares Grant-Date Fair Value 2021 January 4, 2021 (1) 582 $ 14.24 2020 March 2, 2020 (2) 591 $ 19.80 (1) On December 31, 2020, an existing board member was appointed as chair of the board. Reflects the incremental, pro-rated common stock retainer issued for service as chairperson. (2) In March 2020, a new director was appointed to the board of directors of Columbia Property Trust. The new director received a pro-rated annual equity retainer grant at appointment. Stock-Based Compensation Expense For the three months ended March 31, 2021 and 2020, Columbia Property Trust incurred stock-based compensation expense related to the following events (in thousands): Three Months Ended 2021 2020 Amortization of time-based awards $ 1,024 $ 947 Amortization of performance-based awards (1) 1,143 1,031 Amortization of Preferred OP unit awards issued in connection with the Normandy Acquisition 1,832 2,358 Issuance of shares to independent directors 146 12 Total stock-based compensation expense $ 4,145 $ 4,348 (1) Reflects amortization of awards made under the LTI Plan that will vest in future periods for service during the current period. The majority of these expenses are included in general and administrative expenses and management fee expense in the accompanying consolidated statements of operations. As of March 31, 2021 and December 31, 2020, there were $20.4 million and $12.4 million, respectively, of unrecognized compensation costs related to unvested awards under the LTI Plan, which will be amortized over the respective vesting period, ranging from one three

Noncontrolling Interests

Noncontrolling Interests	3 Months Ended
	Mar. 31, 2021
Noncontrolling Interest [Abstract]
Noncontrolling Interests	Noncontrolling Interests Noncontrolling Interest – Columbia OP In connection with the Normandy Acquisition, Columbia Property Trust issued 3,264,151 Series A Convertible, Preferred Units of Columbia OP with a liquidation preference of $26.50 per unit (the "Preferred OP Units"), of which 19,700 were repurchased in the first quarter of 2021. The Preferred OP Units vest over three Noncontrolling Interest – Consolidated Joint Venture Columbia Property Trust holds a 92.5% controlling financial interest in 101 Franklin Street, a 16-story, 235,000-square-foot office building in Manhattan that will be fully redeveloped through a consolidated joint venture with an affiliate of Normandy. The Company owns an additional 0.15% interest in 101 Franklin Street through its interest in Normandy Real Estate Fund IV, L.P. 101 Franklin Street is a variable interest entity, or VIE, in which Columbia Property Trust is the primary beneficiary. Thus, the Company consolidates the accounts of 101 Franklin Street, and reflects the third-party ownership in this entity as noncontrolling interest in the accompanying consolidated balance sheet. As of March 31, 2021, 101 Franklin Street had total assets and liabilities of $4.9 million and $10.0 million, respectively.

Supplemental Disclosures of Non

Supplemental Disclosures of Noncash Investing and Financing Activities	3 Months Ended
	Mar. 31, 2021
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures of Noncash Investing and Financing Activities	Supplemental Disclosures of Noncash Investing and Financing Activities Outlined below are significant noncash investing and financing activities for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended 2021 2020 Other assets assumed at acquisition $ — $ 245 Operating lease asset and liability assumed at acquisition $ — $ 961 Other liabilities assumed at acquisition $ — $ 245 Amortization of net discounts on debt $ 45 $ 45 Accrued capital expenditures and deferred lease costs $ 14,057 $ 15,447 Market value adjustments to interest rate swaps that qualify for hedge accounting treatment $ 4,624 $ (19,993) Issuance of Preferred OP Units for the Normandy Acquisition (Note 3) $ — $ 55,306 Stock-based compensation expense $ 4,144 $ 4,348

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	Leases Columbia Property Trust as Lessee Columbia Property Trust is a lessee on ground leases at certain of its investment properties and office space leases. As of March 31, 2021, Columbia Property Trust has one ground lease at 116 Huntington Avenue in Boston and two office leases. As of March 31, 2021, Columbia Property Trust's ground lease has a remaining lease term of 98.4 years, inclusive of renewal options, and is included, along with our office space leases, in operating lease assets of $38.7 million. Payments for all future periods under this ground lease have already been made. Thus, as of March 31, 2021, operating lease liabilities of $1.8 million include only the present value of future payments due under our office leases, with a weighted-average remaining lease term of 1.6 years, inclusive of renewal options. Columbia Property Trust as Lessor Columbia Property Trust owns and leases commercial real estate, primarily office space, to tenants under operating leases for specified periods of time. Rental income related to such leases is recognized on a straight-line basis over the remaining lease period, and is included in lease revenues on the consolidated statements of operations. As of March 31, 2021, the weighted-average remaining term for such leases is approximately 5.9 years. Lease revenues include fixed and variable payments. Fixed payments primarily relate to base rent and include payments related to lease terminations; and variable payments primarily relate to tenant reimbursements for certain property operating costs. Fixed and variable payments for the three months ended March 31, 2021 and 2020 are as follows (in thousands): For the Three Months Ended March 31, 2021 2020 Fixed payments $ 47,690 $ 61,243 Variable payments 6,619 6,764 Total lease revenues $ 54,309 $ 68,007

Non-Lease Revenues

Non-Lease Revenues	3 Months Ended
	Mar. 31, 2021
Revenue from Contract with Customer [Abstract]
Non-Lease Revenues	Non-Lease Revenues Columbia Property Trust derives most of its revenues from leases, as described in Note 11, Leases . Columbia Property Trust also has the following non-lease revenue streams. Management Fee Revenue Under asset and property management agreements in place with third parties and certain of its unconsolidated joint ventures, Columbia Property Trust earns revenue for performing asset and property management functions for properties owned by the Real Estate Funds and its joint ventures, as further described in Note 4, Unconsolidated Joint Ventures , as well as third-party-owned properties. Asset and property management services are ongoing and routine, and are provided on a recurring basis. Therefore such fees are recognized ratably over the service period, usually a period of three months. For the three months ended March 31, 2021 and 2020, Columbia Property Trust earned management fee revenues of $4.5 million and $4.3 million, respectively. Leasing Fees Under asset and property management agreements in place with third parties and for certain properties owned by joint ventures and the Real Estate Funds, Columbia Property Trust is eligible to earn leasing fees equal to a percentage of the total rental payments to be made by the tenant over the term of the lease. Such fees are required to be recognized when Columbia Property Trust's obligation to perform is complete, typically upon execution of the lease. For the three months ended March 31, 2021 and 2020, Columbia Property Trust earned leasing override fees of $48,400 and $14,600, respectively. Such fees are included in management fee revenue on the accompanying consolidated statements of operations. Construction and Development Fee Income Under construction and development contracts in place with third-party properties and for certain properties owned by joint ventures and the Real Estate Funds, Columbia Property Trust earns fees related to construction and development project management and supervision, using a percentage of completion method, measured by the percentage of costs incurred to date as compared with the estimated total costs for each contract. For the three months ended March 31, 2021 and 2020, Columbia Property Trust earned construction and development fees of $0.3 million and $0.8 million, respectively. Such fees are included in management fee revenue on the accompanying consolidated statements of operations. Salary and Other Reimbursement Revenue Under the property management agreements for third-party-owned properties and certain properties owned through joint ventures and the Real Estate Funds, Columbia Property Trust receives reimbursements for salaries and property operating costs for services that are provided by Columbia Property Trust employees on an ongoing basis. Such reimbursement revenues are recognized ratably over the service period, usually a period of one month, three months, or one year. For the three months ended March 31, 2021 and 2020, Columbia Property Trust earned salary and other reimbursement revenue of $4.0 million and $3.1 million, respectively. These amounts are included in management fee revenues on the accompanying consolidated statements of operations. Miscellaneous Revenue Columbia Property Trust also receives revenues for services provided to its tenants through the TRS Entities, including fitness centers, shuttles, and cafeterias. These revenues are recognized ratably over the service period, usually a period of one month or one quarter. For the three months ended March 31, 2021 and 2020, Columbia Property Trust earned miscellaneous revenue of $0 and $7,100, respectively This amount is included in other property income on the accompanying consolidated statements of operations.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share For the three months ended March 31, 2021 and 2020, in computing the basic and diluted earnings per share, net income (loss) attributable to common stockholders has been reduced for the dividends paid on unvested shares granted under the LTI Plan. The following table reconciles the numerator for the basic and diluted earnings-per-share computations shown on the consolidated statements of operations for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended 2021 2020 Net income $ 445 $ 6,228 Net income attributable to noncontrolling interest in Columbia OP (97) (71) Net loss attributable to noncontrolling interest in consolidated joint venture 129 133 Net income (loss) attributable to common stockholders 477 6,290 Distributions paid on unvested shares (157) (113) Net income (loss) attributable to common stockholders used to calculate basic earnings per share 320 6,177 Net income attributable to noncontrolling interest in Columbia OP 97 71 Net income (loss) attributable to common stockholder and Columbia OP Unit-holders used to calculate diluted earnings per share $ 417 $ 6,248 The following table reconciles the denominator for the basic and diluted earnings-per-share computations shown on the consolidated statements of operations for the three months ended March 31, 2021 and 2020, respectively (in thousands): Three Months Ended 2021 2020 Weighted-average common shares – basic 114,115 114,471 Plus incremental weighted-average shares from time-vested conversions, less assumed stock repurchases: Previously granted awards, unvested — 15 Future period LTI Plan awards 492 — Weighted-average common shares – diluted, before adjustment for OP Units 114,607 114,486 Convertible Preferred OP Units 3,244 2,367 Weighted-average common shares – diluted 117,851 116,853 Certain anti-dilutive stock awards are not included in the current calculation of dilutive weighted average shares, but could be dilutive in the future. As of March 31, 2021, there were 37,400 anti-dilutive shares outstanding, and there were no anti-dilutive shares outstanding as of March 31, 2020.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information Columbia Property Trust considers geographic location when evaluating its portfolio composition, and in assessing the ongoing operations and performance of its properties. As of March 31, 2021, our reportable segments consist of the four key markets in which we own assets: New York, San Francisco, Washington, D.C., and Boston, and the all other markets reportable segment. The all other office markets reportable segment includes properties that are situated similarly within their geographic markets, typically in sub-markets not located within central business districts, and in which Columbia Property Trust does not have a substantial presence and/or does not plan to make further investments. During the periods presented, there have been no material intersegment transactions. Net operating income ("NOI") is a non-GAAP financial measure. NOI is the primary performance measure reviewed by management to assess operating performance of properties and is calculated by deducting operating expenses from operating revenues. Operating revenues include lease revenues and other property income; and operating expenses include property operating costs. The NOI performance metric consists only of revenues and expenses directly related to real estate rental operations. NOI reflects property acquisitions and dispositions, occupancy levels, rental rate increases or decreases, and the recoverability of operating expenses. NOI, as Columbia Property Trust calculates it, may not be directly comparable to similarly titled, but differently calculated, measures for other REITs. Asset information and capital expenditures by segment are not reported because Columbia Property Trust does not use these measures to assess performance. Depreciation and amortization expense, along with other expense and income items, are not allocated among segments. The following table presents operating revenues included in NOI by geographic reportable segment for Columbia Property Trust's respective ownership interests (in thousands): Three Months Ended March 31, 2021 2020 New York (1) $ 40,129 $ 41,105 San Francisco (2) 29,125 34,801 Washington, D.C. (3) 14,432 15,018 Boston 3,969 4,149 All other office markets — 2,587 Total office segments 87,655 97,660 Corporate (583) (373) Total operating revenues $ 87,072 $ 97,287 (1) Includes operating revenues for two unconsolidated properties, based on Columbia Property Trust's ownership interests: 49.5% for 114 Fifth Avenue for all periods presented; and 8.65% for Terminal Warehouse from March 13, 2020 through March 31, 2021. (2) Includes operating revenues for three unconsolidated properties, 333 Market Street and University Circle, based on Columbia Property Trust's ownership interests: 55.0% for all periods presented; and 221 Main Street, based on Columbia Property Trust's ownership interests: 100% from January 1, 2020 to October 7, 2020, and 55% from October 8, 2020 to March 31, 2021. (3) Includes operating revenues for two unconsolidated properties, Market Square and 1800 M Street, based on Columbia Property Trust's ownership interests: 51.0% for Market Square and 55.0% for 1800 M Street for all periods presented. A reconciliation of GAAP revenues to operating revenues is presented below (in thousands): Three Months Ended March 31, 2021 2020 Total revenues $ 64,388 $ 76,254 Operating revenues included in income from unconsolidated joint ventures (1) 32,763 29,273 Less: management fee revenue (2) (10,079) (8,240) Total operating revenues $ 87,072 $ 97,287 (1) Columbia Property Trust records its interest in properties held through unconsolidated joint ventures using the equity method of accounting, and reflects its interest in the operating revenues of these properties in income from unconsolidated joint ventures in the accompanying consolidated statements of operations. (2) See Note 12, Non-Lease Revenues , of the accompanying consolidated financial statements. The following table presents NOI by geographic reportable segment (in thousands): Three Months Ended March 31, 2021 2020 New York (1) $ 27,417 $ 25,075 San Francisco (2) 19,939 25,072 Washington, D.C. (3) 8,169 9,151 Boston 2,186 2,458 All other office markets — 1,525 Total office segments 57,711 63,281 Corporate (497) (272) Total NOI $ 57,214 $ 63,009 (1) Includes NOI for three unconsolidated properties, based on Columbia Property Trust's ownership interest: 49.5% for 114 Fifth Avenue for all periods presented; 49.7% for 799 Broadway for all periods presented; and 8.65% for Terminal Warehouse from March 13, 2020 through March 31, 2021. (2) Includes NOI for three unconsolidated properties, 333 Market Street and University Circle, based on Columbia Property Trust's ownership interests: 55.0% for all periods presented; and 221 Main Street, based on Columbia Property Trust's ownership interests: 100% from January 1, 2020 to October 7, 2020, and 55% from October 8, 2020 to March 31, 2021. (3) Includes NOI for two unconsolidated properties, Market Square and 1800 M Street, based on Columbia Property Trust's ownership interests: 51.0% for the Market Square and 55.0% for 1800 M Street for all periods presented. A reconciliation of GAAP net income to NOI is presented below (in thousands): Three Months Ended March 31, 2021 2020 Net income attributable to common stockholders $ 477 $ 6,290 Management fee revenues (10,079) (8,240) Depreciation 16,531 18,330 Amortization 4,844 6,721 General and administrative 9,776 11,782 Strategic review costs 2,356 — Management fee expenses 9,269 6,945 Acquisition costs — 12,081 Net interest expense 7,535 9,553 Market value adjustments to investment in Real Estate Funds 239 160 Income tax expense (benefit) (329) (2,243) Adjustments included in income from unconsolidated joint ventures 16,627 14,903 Gain on sale of real estate assets — (13,344) Adjustments attributable to noncontrolling interests (32) 71 NOI $ 57,214 $ 63,009

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Columbia Property Trust has evaluated subsequent events in connection with the preparation of its consolidated financial statements and notes thereto included in this report and noted the Terminal Warehouse loan extension, as described in Note 3, Transactions .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements of Columbia Property Trust have been prepared in accordance with the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by U.S. generally accepted accounting principles ("GAAP") for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair and consistent presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year's results. For additional information on Columbia Property Trust's unconsolidated joint ventures, which are accounted for using the equity method of accounting, see Note 4, Unconsolidated Joint Ventures
Fair Value Measurements	Fair Value Measurements Columbia Property Trust estimates the fair value of its assets and liabilities (where currently required under GAAP) consistent with the provisions of Accounting Standard Codification 820, Fair Value Measurements ("ASC 820"). Under this standard, fair value is defined as the price that would be received upon sale of an asset or paid upon transfer of a liability in an orderly transaction between market participants at the measurement date, under current market conditions. While various techniques and assumptions can be used to estimate fair value depending on the nature of the asset or liability, the accounting standard for fair value measurements and disclosures provides the following fair value technique parameters and hierarchy, depending upon availability: Level 1 – Assets or liabilities for which the identical term is traded on an active exchange, such as publicly traded instruments or futures contracts. Level 2 – Assets or liabilities valued based on observable market data for similar instruments.
Real Estate Assets	Real Estate Assets Columbia Property Trust is required to make subjective assessments as to the useful lives of its depreciable assets. To determine the appropriate useful life of an asset, Columbia Property Trust considers the period of future benefit of the asset. These assessments have a direct impact on net income. The estimated useful lives of its assets by class are as follows: Buildings 40 years Building and site improvements 5-25 years Tenant improvements Shorter of economic life or lease term Intangible lease assets Lease term
Assets Held for Sale	Assets Held for Sale Columbia Property Trust classifies properties as held for sale according to Accounting Standard Codification 360, Accounting for the Impairment or Disposal of Long-Lived Assets ("ASC 360"). According to ASC 360, properties having separately identifiable operations and cash flows are considered held for sale when all of the following criteria are met: • Management, having the authority to approve the action, commits to a plan to sell the property. • The property is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such property. • An active program to locate a buyer and other actions required to complete the plan to sell the property have been initiated. • The property is being actively marketed for sale at a price that is reasonable in relation to its current fair value. • Actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. • The sale of the property is probable (i.e., typically subject to a binding sale contract with a non-refundable deposit), and transfer of the property is expected to qualify for recognition as a completed sale within one year.
Evaluating the Recoverability of Real Estate Assets	Evaluating the Recoverability of Real Estate Assets Columbia Property Trust continually monitors events and changes in circumstances that could indicate that the net carrying amounts of its real estate and related intangible assets and liabilities, of both operating properties and properties under development or redevelopment, may not be recoverable. When indicators of potential impairment are present that suggest that the net carrying amounts of real estate assets and related intangible assets and liabilities may not be recoverable, Columbia Property Trust assesses the recoverability of these net assets by determining whether the respective carrying values will be recovered through the estimated undiscounted future cash flows expected from the use of the net assets and their eventual disposition. In the event that such expected undiscounted future cash flows do not exceed the carrying values, Columbia Property Trust adjusts the carrying values of the real estate assets and related intangible assets and liabilities to the estimated fair values, pursuant to the property, plant, and equipment accounting standard for the impairment or disposal of long-lived assets, and recognizes an impairment loss. At such time that a
Intangible Assets and Liabilities Arising From In-Place Leases Where Columbia Property Trust Is the Lessor	Intangible Assets and Liabilities Arising From In-Place Leases Where Columbia Property Trust Is the LessorUpon the acquisition of real properties, Columbia Property Trust allocates the purchase price of the properties to tangible assets, consisting of land, building, site improvements, and identified intangible assets and liabilities, including the value of in-place leases, based in each case on Columbia Property Trust's estimate of their fair values in accordance with ASC 820 (see "Fair Value Measurements" section above for additional detail).
Investments in Unconsolidated Joint Ventures/Investments in Real Estate Funds/Noncontrolling Interests	Investments in Unconsolidated Joint Ventures Columbia Property Trust uses the equity method to account for investments that are not wholly owned and: (i) are considered variable interest entities where the Company is not the primary beneficiary, or (ii) in which the Company, along with its co-owners, possesses substantive participation rights, including management selection and termination, and the approval of significant capital and operating decisions. Under the equity method, investments in unconsolidated joint ventures are recorded at cost and adjusted for cash contributions and distributions, and allocations of income or loss. Investments in Real Estate Funds Columbia Property Trust holds general partnership interests and limited partnership interests in three real estate funds: Normandy Real Estate Fund III, LP; Normandy Real Estate Fund IV, LP; and Normandy Opportunity Zone Fund, LP (collectively, the "Real Estate Funds"). The Company owns minimal economic interests in the Real Estate Funds (ranging from 2.0% to 2.5%). Significant decision rights are shared between the general partners and limited partners and a general partner can be removed with a majority vote from the limited partners. As a result, Columbia Property Trust accounts for its investments in the Real Estate Funds using the equity method. The Real Estate Funds are subject to the rules of the AICPA Investment Company Guide; as a result, GAAP requires the Company to record its investments in the Real Estate Funds at their respective estimated fair market values. The Company determines the Real Estate Funds' estimated net asset values per share using a discounted cash flow model, which is considered a Level 3 valuation technique (see "Fair Value Measurements " section above). As of March 31, 2021 and December 31, 2020, investments in the Real Estate Funds of approximately $4.2 million and $4.3 million, respectively, are included in prepaid expenses and other assets on the accompanying consolidated balance sheet. For the three months ended March 31, 2021 and 2020, Columbia Property Trust recognized unrealized losses on its investments in Real Estate Funds of approximately $0.2 million, which are recorded as other income (loss) in the accompanying consolidated statements of operations. Columbia Property Trust has entered into agreements to provide acquisition, disposition, investment management, property management, leasing, and other services to the properties in which the Real Estate Funds own interests. See Note 12, Non-Lease Revenues , for more details. From time to time, Columbia Property Trust may be required to make additional capital contributions to the Real Estate Funds. See Note 7, Commitments and Contingencies , for more details . Noncontrolling Interests Noncontrolling interests represent the portion of equity in consolidated entities that is owned by third parties. Noncontrolling interests are adjusted for cash contributions and distributions, and for earnings. Such earnings are allocated between the Company and noncontrolling interests using the hypothetical liquidation at book value method
Tenant Receivables	Tenant Receivables Tenant receivables consist of rental and reimbursement billings due from tenants. Tenant receivables are recorded at the original amount earned, which approximates fair value. Management assesses the realizability of tenant receivables on an ongoing basis. When the collectability of tenant receivables is not considered probable, the receivable is written down against lease revenues. During the three months ended March 31, 2021 and 2020, $1,340,000 and $8,000, respectively, of tenant receivables were written down against lease revenues.
Straight-Line Rent Receivable	Straight-Line Rent Receivable Straight-line rent receivable reflects the amount of cumulative adjustments necessary to present rental income on a straight-line basis. Columbia Property Trust recognizes rental revenues on a straight-line basis, ratably over the term of each lease; however, leases often provide for payment terms that differ from the revenue recognized. When the amount of cash billed is less than the amount of revenue recognized, typically early in the lease, straight-line rent receivable is recorded for the difference. The receivable is depleted during periods later in the lease when the amount of cash paid by the tenant is greater than the amount of revenue recognized. When the collection of future rental billings is not considered probable, tenants are moved to "cash basis billings," at which point the corresponding straight-line rent receivable is written-down against lease revenues, and future revenues are recognized upon receipt of payment. During the three months ended March 31, 2021, approximately $0.2 million of straight-line rent receivables were written down against lease revenues.
Interest Rate Swap Agreements	Interest Rate Swap AgreementsColumbia Property Trust enters into interest rate swap contracts to mitigate its interest rate risk on the related financial instruments. Columbia Property Trust does not enter into derivative or interest rate swap transactions for speculative purposes and currently does not have any derivatives that are not designated as hedges; however, certain of its derivatives may, at times, not qualify for hedge accounting treatment. Columbia Property Trust records the fair value of its interest rate swaps on its consolidated balance sheet either as prepaid expenses and other assets or as accounts payable, accrued expenses, and accrued capital expenditures. Changes in the fair value of interest rate swaps that are designated as cash flow hedges are recorded as other comprehensive income (loss). Changes in the fair value of interest rate swaps that do not qualify for hedge accounting treatment are recorded as gain or loss on interest rate swaps. Amounts received or paid under interest rate swap agreements are recorded as interest expense for contracts that qualify for hedge accounting treatment and as gain or loss on interest rate swaps for contracts that do not qualify for hedge accounting treatment.
Income Taxes	Income Taxes Columbia Property Trust has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the "Code") and has operated as such beginning with its taxable year ended December 31, 2003. To qualify as a REIT, the Company must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its REIT taxable income, as defined by the Code, to its stockholders. To the extent that Columbia Property Trust satisfies the distribution requirement but distributes less than 100% of its REIT taxable income, the Company would be subject to federal and state corporate income tax on the undistributed income. Generally, the Company does not incur federal income taxes, other than as described in the following paragraph, because its stockholder distributions typically exceed its taxable income due to noncash expenses such as depreciation. Columbia Property Trust is, however, subject to certain state and local taxes related to the operations of properties in certain locations, which have been provided for in the accompanying consolidated financial statements. Columbia Property Trust TRS, LLC; Columbia KCP TRS, LLC; Columbia Development TRS 13, LLC; and Columbia Development TRS 87, LLC (collectively, the "TRS Entities") are subsidiaries of the Company and are organized as Delaware limited liability companies. The TRS Entities, among other things, provide services related to asset and property management, construction and development, and other tenant services that Columbia Property Trust, as a REIT, cannot otherwise provide. The Company has elected to treat the TRS Entities as taxable REIT subsidiaries. Columbia Property Trust may perform certain additional, noncustomary services for tenants of its buildings through the TRS Entities; however, earnings of a TRS entity are subject to federal and state income taxes. In addition, for the Company to continue to qualify as a REIT, Columbia Property Trust must limit its investments in taxable REIT subsidiaries to 20% of the value of the total assets. The TRS Entities' deferred tax assets and liabilities represent temporary differences between the financial reporting basis and the tax basis of assets and liabilities based on the enacted rates expected to be in effect when the temporary differences reverse. If applicable, the Company records interest and penalties related to uncertain tax positions as general and administrative expense in the accompanying consolidated statements of operations.
Reclassification	Reclassification Certain prior-period amounts on the consolidated statement of cash flows have been reclassified to conform with the current-period presentation. With respect to adjustments to reconcile net income to cash provided by operating activities, lease revenues reserved for doubtful accounts – tenant receivables includes amounts previously reported in decrease (increase) in tenant receivables, net.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Standard Update 2021-01, Reference Rate Reform ("ASC 2021-01"), which was issued on and effective as of January 7, 2021, refines the scope of ASC 848, Reference Rate Reform ("ASC 848"), which was codified last year to address the accounting and disclosure impacts of reference rate reform and the anticipated discontinuance of LIBOR. Columbia Property Trust has matched LIBOR-based debt with LIBOR-based interest rate swaps, and has elected to apply the practical expedients provided for in ASC 848 related to (i) probability and (ii) the assessment of the effectiveness for future LIBOR-indexed cash flows, which assume that the debt instrument will use the same index rate as its corresponding interest rate swap, once a new reference rate is established to replace LIBOR. Application of these expedients preserves the effectiveness of the Company's interest rate swaps as cash flow hedges in the event that its debt and interest rate swaps are not amended concurrently to reflect a new reference rate. ASC 2021-01 allows for entities to either apply the practical expedient as Columbia has elected to do, or change its effectiveness approach to a quantitative model as provided for in existing guidance. Columbia Property Trust continues to evaluate the impact of the guidance and may apply other elections as additional reference rate changes occur. ASC 848 and ASU 2021-01 may be

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Schedule of Estimated Useful Lives for Real Estate Assets	The estimated useful lives of its assets by class are as follows: Buildings 40 years Building and site improvements 5-25 years Tenant improvements Shorter of economic life or lease term Intangible lease assets Lease term
Schedule of Intangible Assets and Liabilities	As of March 31, 2021 and December 31, 2020, Columbia Property Trust had the following intangible assets and liabilities, arising from in-place leases, excluding amounts held for sale, if applicable (in thousands): Intangible Lease Assets Intangible Intangible Above-Market Absorption March 31, 2021 Gross $ 2,480 $ 99,153 $ 55,814 $ 21,281 Accumulated Amortization (1,416) (56,554) (35,662) (7,582) Net $ 1,064 $ 42,599 $ 20,152 $ 13,699 December 31, 2020 Gross $ 2,480 $ 101,542 $ 56,612 $ 23,287 Accumulated Amortization (1,374) (56,573) (35,161) (8,867) Net $ 1,106 $ 44,969 $ 21,451 $ 14,420 Amortization of Intangible Assets and Liabilities Arising From In-Place Leases For the three months ended March 31, 2021 and 2020, Columbia Property Trust recognized the following amortization of intangible lease assets and liabilities (in thousands): Intangible Lease Assets Intangible Intangible Above-Market Absorption For the Three Months Ended March 31, 2021 $ 42 $ 2,369 $ 1,299 $ 722 For the Three Months Ended March 31, 2020 $ 43 $ 3,700 $ 1,586 $ 1,596 The net intangible assets and liabilities remaining as of March 31, 2021 will be amortized as follows, excluding amounts held for sale, if applicable (in thousands): Intangible Lease Assets Intangible Intangible Above-Market Absorption For the remainder of 2021 $ 129 $ 6,594 $ 3,111 $ 2,080 For the years ending December 31: 2022 172 7,620 3,335 2,571 2023 172 6,138 2,810 1,995 2024 172 5,333 2,500 1,748 2025 172 3,943 1,849 1,182 2026 109 2,832 1,321 964 Thereafter 138 10,139 5,226 3,159 $ 1,064 $ 42,599 $ 20,152 $ 13,699
Schedule of Interest Rate Swaps	The following tables provide additional information related to Columbia Property Trust's interest rate swaps (in thousands): Estimated Fair Value as of Instrument Type Balance Sheet Classification March 31, December 31, Derivatives Designated as Hedging Instruments: Interest rate contracts Accounts payable $ 14,096 $ 18,720
Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position	Three Months Ended 2021 2020 Market value adjustment to interest rate swaps designated as hedging instruments and included in other comprehensive income (loss) $ 4,624 $ (19,993)

Transactions (Tables)

Transactions (Tables)	3 Months Ended
	Mar. 31, 2021
Real Estate [Abstract]
Assets and Liabilities Held For Sale	Additional information for certain of the disposition transactions is provided below the table. There have been no real estate dispositions in 2021 to date. Property Location Date % Sold Sales Price (1) (in thousands) Gain (loss) on Sale 2020 221 Main Street San Francisco, CA October 8, 2020 45 % $ 180,000 $ 175,271 Pasadena Corporate Park Los Angeles, CA March 31, 2020 100 % $ 78,000 $ (67) Cranberry Woods Drive Pittsburgh, PA January 16, 2020 100 % $ 180,000 $ 13,428 (1) Exclusive of transaction costs and price adjustments.
Schedule of Properties Acquired	The initial purchase consideration was allocated as follows (in thousands): January 24, 2020 Goodwill (1) $ 63,806 Prepaid expenses and other assets (2) 7,670 Cash 1,260 Operating lease assets 934 Investments in unconsolidated joint ventures (3) 419 Accounts payable, accrued expenses, and accrued capital expenditures (2,881) Operating lease liabilities (934) Deferred income (77) Total initial purchase consideration $ 70,197 (1) In the fourth quarter of 2020, in connection with Columbia's annual assessment of the recoverability of goodwill, the Company wrote off this balance by recording an impairment loss of $63.8 million. (2) Prepaid expenses and other assets includes $3.7 million of investments in Real Estate Funds, as described in Note 2, Summary of Significant Accounting Policies . (3) Reflects interests in five unconsolidated joint ventures that earn fees for providing management services to properties affiliated with the Real Estate Funds.

Unconsolidated Joint Ventures (

Unconsolidated Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Summary of Financial Information for the Joint Ventures	As of March 31, 2021 and December 31, 2020, Columbia Property Trust owned interests in the following properties through joint ventures, which are accounted for using the equity method of accounting (in thousands): Carrying Value of Investment (1) Joint Venture Property Name Geographic Market Ownership Interest March 31, 2021 December 31, 2020 University Circle Joint Venture University Circle San Francisco 55.00 % $ 275,867 $ 276,574 333 Market Street Joint Venture 333 Market Street San Francisco 55.00 % 264,483 265,673 1800 M Street Joint Venture 1800 M Street Washington, D.C. 55.00 % 225,888 227,847 221 Main Street Joint Venture 221 Main Street San Francisco, CA 55.00 % 217,057 219,078 114 Fifth Avenue Joint Venture 114 Fifth Avenue New York 49.50 % 75,367 74,273 Market Square Joint Venture Market Square Washington, D.C. 51.00 % 133,726 134,747 799 Broadway Joint Venture (2) 799 Broadway New York, NY 49.70 % 55,888 53,248 Terminal Warehouse Joint Venture (2) Terminal Warehouse New York, NY 8.65 % 46,571 43,771 Real Estate Services Joint Ventures (3) n/a (3) n/a (3) Various (3) 572 589 $ 1,295,419 $ 1,295,800 (1) Includes basis differences. There are aggregate net differences between the historical costs recorded at the joint venture level, and Columbia Property Trust's investments in unconsolidated joint ventures of $382.1 million and $383.5 million as of March 31, 2021 and December 31, 2020, respectively. Such basis differences result from the timing of each partner's joint venture interest acquisition; and formation costs incurred by Columbia Property Trust. Basis differences are amortized to income (loss) from unconsolidated joint ventures over the lives of the underlying assets or liabilities. (2) Columbia Property Trust capitalized interest on its investment in the 799 Broadway Joint Venture and the Terminal Warehouse Joint Venture: $0.8 million and $0.3 million during the three months ended March 31, 2021 and 2020, respectively. (3) Columbia Property Trust owns the following interests in five unconsolidated joint ventures that earn fees for providing real estate management services to properties affiliated with the Real Estate Funds (the "Real Estate Services Joint Ventures"): L&L Normandy Terminal Asset Manager, LLC (67%); L&L Normandy Terminal Development Manager, LLC (50%); L&L Normandy Terminal Property Manager (50%) (collectively, the "Terminal Services Joint Ventures"); WNK Maiden Management (50%); and Maple AB Services, LLC (55%). The Terminal Services Joint Ventures earn fees from providing services to the Terminal Warehouse Joint Venture. Summarized balance sheet information for each of the unconsolidated joint ventures is as follows (in thousands): Total Assets Total Debt Total Equity (1) March 31, December 31, 2020 March 31, December 31, 2020 March 31, December 31, 2020 University Circle Joint Venture $ 214,280 $ 213,045 $ — $ — $ 208,653 $ 208,541 333 Market Street Joint Venture 354,835 357,370 — — 341,676 344,103 1800 M Street Joint Venture 421,219 427,602 — — 408,417 411,957 221 Main Street Joint Venture 230,231 229,745 — — 224,523 224,732 114 Fifth Avenue Joint Venture 464,030 462,319 — — 104,567 101,952 Market Square Joint Venture 568,545 577,095 324,881 (2) 324,868 235,187 237,778 799 Broadway Joint Venture 255,670 246,456 144,116 (3) 138,930 103,249 99,000 Terminal Warehouse Joint Venture 1,079,057 1,045,852 645,081 (4) 643,819 406,725 380,277 Real Estate Services Joint Ventures 1,581 1,754 — — 977 1,104 $ 3,589,448 $ 3,561,238 $ 1,114,078 $ 1,107,617 $ 2,033,974 $ 2,009,444 (1) Excludes basis differences (see footnote (1) to the Carrying Value of Investment table above), which are amortized to income (loss) from unconsolidated joint ventures over the lives of the underlying assets or liabilities. (2) The Market Square Joint Venture has a $325.0 million mortgage note. The Market Square mortgage note bears interest at 5.07% and matures on July 1, 2023. (3) Reflects $145.1 million outstanding, net of $1.0 million of net unamortized deferred financing costs, on the 799 Broadway construction loan. The 799 Broadway construction loan is being used to finance a portion of the 799 Broadway development project, has total capacity of $187.0 million, and bears interest at LIBOR plus a spread of 425 basis points, with a LIBOR floor of 1.00% and capped of 4.00% (the "Construction Loan"). A portion of the monthly interest payments accrue into the balance of the loan. The Construction Loan matures on October 9, 2021, with two one-year extension options. For a discussion of Columbia Property Trust's equity guaranty related to the Construction Loan, see Note 7, Commitments and Contingencies . (4) Reflects $645.5 million outstanding, net of $0.4 million of net unamortized deferred financing costs, on the Terminal Warehouse acquisition loan. The Terminal Warehouse Joint Venture has an interest-only acquisition loan with a total capacity of $650.0 million. The Terminal Warehouse acquisition loan bears interest at LIBOR plus a spread of 340 basis points, with a LIBOR floor of 2.28% and cap of 3.50%, and matures on May 24, 2021, with two extension options for a total possible extension period of eight Summarized income statement information for the unconsolidated joint ventures for the three months ended March 31, 2021 and 2020 is as follows (in thousands): Total Revenues Net Income (Loss) Columbia Property Trust's Share of Net Income (Loss) (1) 2021 2020 2021 2020 2021 2020 University Circle Joint Venture $ 10,305 $ 10,924 $ 5,112 $ 5,715 $ 2,811 $ 3,144 333 Market Street Joint Venture 7,135 7,067 3,672 3,705 2,020 2,037 1800 M Street Joint Venture 9,631 9,937 1,463 1,752 805 964 221 Main Street Joint Venture 7,982 — 2,583 — 1,420 — 114 Fifth Avenue Joint Venture 10,735 10,428 6,865 (2,653) 3,398 (1,314) Market Square Joint Venture 12,597 12,690 (2,586) (1,994) (1,319) (1,017) 799 Broadway Joint Venture — — (40) (32) (20) (16) Terminal Warehouse Joint Venture 2,173 2,307 (2,152) (3,741) (186) (324) Real Estate Services Joint Ventures 1,889 1,875 962 938 565 341 $ 62,447 $ 55,228 $ 15,879 $ 3,690 $ 9,494 $ 3,815 (1) Excludes amortization of basis differences (see footnote to (1) the Carrying Value of Investment table above), which are recorded as income (loss) from unconsolidated joint ventures in the accompanying consolidated statements of operations.
Summary of Fees Earned from Unconsolidated Joint Ventures	During the three months ended March 31, 2021 and 2020, Columbia Property Trust earned the following fees from its unconsolidated joint ventures (in thousands): Three Months Ended 2021 2020 University Circle Joint Venture $ 587 $ 587 333 Market Street Joint Venture 209 214 1800 M Street Joint Venture 562 555 221 Main Street Joint Venture 471 — Market Square Joint Venture 605 574 799 Broadway Joint Venture — 223 $ 2,434 $ 2,153

Line of Credit and Notes Paya_2

Line of Credit and Notes Payable (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Schedule of Line of Credit and Notes Payable Indebtedness	As of March 31, 2021 and December 31, 2020, Columbia Property Trust had the following line of credit and notes payable indebtedness (excluding bonds payable; see Note 6, Bonds Payable ) (in thousands): Facility March 31, December 31, $300 Million Term Loan $ 300,000 $ 300,000 $150 Million Term Loan 150,000 150,000 Revolving Credit Facility 124,000 110,000 Less: Deferred financing costs related to term loans and notes payable, net of accumulated amortization (1,316) (1,470) $ 572,684 $ 558,530

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Summary of the Activity of Employee Stock Grants	Below is a summary of the employee awards issued under the LTI Plan during the three months ended March 31, 2021: Time-Based Awards Performance-Based Awards Restricted Shares Weighted-Average Grant-Date Fair Value (1) RSUs Weighted-Average Grant-Date Fair Value (2) Unvested awards – beginning of period 497 $ 20.82 715 $ 18.51 Granted 422 $ 14.33 430 $ 12.39 Converted (3) 24 (24) Vested (4) (195) $ 21.32 (73) $ 20.66 Forfeited (2) $ 14.34 (1) $ 12.39 Unvested awards – end of period (5) 746 $ 15.75 1,047 $ 15.16 (1) Reflects the weighted-average, grant-date fair value using the market closing price on the date of the respective grants. (2) Reflects the weighted-average, grant-date fair value using a Monte Carlo valuation. (3) Reflects 25% of the 2018 3-year Performance-Based RSUs granted on January 1, 2018, which converted to Time-Based Restricted shares in January 2021 and will vest in January 2022. (4) With respect to the RSUs vesting this period, includes true-ups from the amount granted (based on target-level performance) to the respective amount paid (based on actual performance, as defined by the plan). (5) As of March 31, 2021, Columbia Property Trust expects approximately 712,000 of the 746,000 unvested restricted stock units to ultimately vest and approximately 1,000,000 of the 1,047,000 unvested Performance-Based RSUs to ultimately vest, assuming a weighted-average forfeiture rate of 4.5%, which was determined based on historical forfeiture rates.
Schedule of Director Stock Grants	During the three months ended March 31, 2021 and 2020, Columbia Property Trust made the following equity retainer grants: Date of Grant Shares Grant-Date Fair Value 2021 January 4, 2021 (1) 582 $ 14.24 2020 March 2, 2020 (2) 591 $ 19.80 (1) On December 31, 2020, an existing board member was appointed as chair of the board. Reflects the incremental, pro-rated common stock retainer issued for service as chairperson. (2) In March 2020, a new director was appointed to the board of directors of Columbia Property Trust. The new director received a pro-rated annual equity retainer grant at appointment.
Schedule of Stock-based Compensation Expense Incurred	For the three months ended March 31, 2021 and 2020, Columbia Property Trust incurred stock-based compensation expense related to the following events (in thousands): Three Months Ended 2021 2020 Amortization of time-based awards $ 1,024 $ 947 Amortization of performance-based awards (1) 1,143 1,031 Amortization of Preferred OP unit awards issued in connection with the Normandy Acquisition 1,832 2,358 Issuance of shares to independent directors 146 12 Total stock-based compensation expense $ 4,145 $ 4,348 (1) Reflects amortization of awards made under the LTI Plan that will vest in future periods for service during the current period.

Supplemental Disclosures of N_2

Supplemental Disclosures of Noncash Investing and Financing Activities (Tables)	3 Months Ended
	Mar. 31, 2021
Supplemental Cash Flow Elements [Abstract]
Significant Noncash Investing and Financing Activities	Outlined below are significant noncash investing and financing activities for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended 2021 2020 Other assets assumed at acquisition $ — $ 245 Operating lease asset and liability assumed at acquisition $ — $ 961 Other liabilities assumed at acquisition $ — $ 245 Amortization of net discounts on debt $ 45 $ 45 Accrued capital expenditures and deferred lease costs $ 14,057 $ 15,447 Market value adjustments to interest rate swaps that qualify for hedge accounting treatment $ 4,624 $ (19,993) Issuance of Preferred OP Units for the Normandy Acquisition (Note 3) $ — $ 55,306 Stock-based compensation expense $ 4,144 $ 4,348

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Summary of Fixed and Variable Revenues	Fixed and variable payments for the three months ended March 31, 2021 and 2020 are as follows (in thousands): For the Three Months Ended March 31, 2021 2020 Fixed payments $ 47,690 $ 61,243 Variable payments 6,619 6,764 Total lease revenues $ 54,309 $ 68,007

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share Computations	The following table reconciles the numerator for the basic and diluted earnings-per-share computations shown on the consolidated statements of operations for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended 2021 2020 Net income $ 445 $ 6,228 Net income attributable to noncontrolling interest in Columbia OP (97) (71) Net loss attributable to noncontrolling interest in consolidated joint venture 129 133 Net income (loss) attributable to common stockholders 477 6,290 Distributions paid on unvested shares (157) (113) Net income (loss) attributable to common stockholders used to calculate basic earnings per share 320 6,177 Net income attributable to noncontrolling interest in Columbia OP 97 71 Net income (loss) attributable to common stockholder and Columbia OP Unit-holders used to calculate diluted earnings per share $ 417 $ 6,248 The following table reconciles the denominator for the basic and diluted earnings-per-share computations shown on the consolidated statements of operations for the three months ended March 31, 2021 and 2020, respectively (in thousands): Three Months Ended 2021 2020 Weighted-average common shares – basic 114,115 114,471 Plus incremental weighted-average shares from time-vested conversions, less assumed stock repurchases: Previously granted awards, unvested — 15 Future period LTI Plan awards 492 — Weighted-average common shares – diluted, before adjustment for OP Units 114,607 114,486 Convertible Preferred OP Units 3,244 2,367 Weighted-average common shares – diluted 117,851 116,853

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Reconciliation of Revenue from Segments to Consolidated	The following table presents operating revenues included in NOI by geographic reportable segment for Columbia Property Trust's respective ownership interests (in thousands): Three Months Ended March 31, 2021 2020 New York (1) $ 40,129 $ 41,105 San Francisco (2) 29,125 34,801 Washington, D.C. (3) 14,432 15,018 Boston 3,969 4,149 All other office markets — 2,587 Total office segments 87,655 97,660 Corporate (583) (373) Total operating revenues $ 87,072 $ 97,287 (1) Includes operating revenues for two unconsolidated properties, based on Columbia Property Trust's ownership interests: 49.5% for 114 Fifth Avenue for all periods presented; and 8.65% for Terminal Warehouse from March 13, 2020 through March 31, 2021. (2) Includes operating revenues for three unconsolidated properties, 333 Market Street and University Circle, based on Columbia Property Trust's ownership interests: 55.0% for all periods presented; and 221 Main Street, based on Columbia Property Trust's ownership interests: 100% from January 1, 2020 to October 7, 2020, and 55% from October 8, 2020 to March 31, 2021. (3) Includes operating revenues for two unconsolidated properties, Market Square and 1800 M Street, based on Columbia Property Trust's ownership interests: 51.0% for Market Square and 55.0% for 1800 M Street for all periods presented. A reconciliation of GAAP revenues to operating revenues is presented below (in thousands): Three Months Ended March 31, 2021 2020 Total revenues $ 64,388 $ 76,254 Operating revenues included in income from unconsolidated joint ventures (1) 32,763 29,273 Less: management fee revenue (2) (10,079) (8,240) Total operating revenues $ 87,072 $ 97,287 (1) Columbia Property Trust records its interest in properties held through unconsolidated joint ventures using the equity method of accounting, and reflects its interest in the operating revenues of these properties in income from unconsolidated joint ventures in the accompanying consolidated statements of operations. (2) See Note 12, Non-Lease Revenues , of the accompanying consolidated financial statements.
Schedule of Segment Reporting Information, by Segment	The following table presents NOI by geographic reportable segment (in thousands): Three Months Ended March 31, 2021 2020 New York (1) $ 27,417 $ 25,075 San Francisco (2) 19,939 25,072 Washington, D.C. (3) 8,169 9,151 Boston 2,186 2,458 All other office markets — 1,525 Total office segments 57,711 63,281 Corporate (497) (272) Total NOI $ 57,214 $ 63,009 (1) Includes NOI for three unconsolidated properties, based on Columbia Property Trust's ownership interest: 49.5% for 114 Fifth Avenue for all periods presented; 49.7% for 799 Broadway for all periods presented; and 8.65% for Terminal Warehouse from March 13, 2020 through March 31, 2021. (2) Includes NOI for three unconsolidated properties, 333 Market Street and University Circle, based on Columbia Property Trust's ownership interests: 55.0% for all periods presented; and 221 Main Street, based on Columbia Property Trust's ownership interests: 100% from January 1, 2020 to October 7, 2020, and 55% from October 8, 2020 to March 31, 2021. (3) Includes NOI for two unconsolidated properties, Market Square and 1800 M Street, based on Columbia Property Trust's ownership interests: 51.0% for the Market Square and 55.0% for 1800 M Street for all periods presented. A reconciliation of GAAP net income to NOI is presented below (in thousands): Three Months Ended March 31, 2021 2020 Net income attributable to common stockholders $ 477 $ 6,290 Management fee revenues (10,079) (8,240) Depreciation 16,531 18,330 Amortization 4,844 6,721 General and administrative 9,776 11,782 Strategic review costs 2,356 — Management fee expenses 9,269 6,945 Acquisition costs — 12,081 Net interest expense 7,535 9,553 Market value adjustments to investment in Real Estate Funds 239 160 Income tax expense (benefit) (329) (2,243) Adjustments included in income from unconsolidated joint ventures 16,627 14,903 Gain on sale of real estate assets — (13,344) Adjustments attributable to noncontrolling interests (32) 71 NOI $ 57,214 $ 63,009

Organization (Details)

Organization (Details)	Mar. 13, 2020ft²	Mar. 31, 2021ft²property
Real Estate Properties [Line Items]
Square feet of real estate | ft²		6,200,000
Percent of leased office space of owned properties		94.00%
Office Building
Real Estate Properties [Line Items]
Number of real estate properties		15
Number of properties under development		4
Office Building | Corporate Joint Venture
Real Estate Properties [Line Items]
Number of real estate properties		9
Asset and Property Management Services Office Space
Real Estate Properties [Line Items]
Square feet of real estate | ft²		8,000,000
Wholly Owned Properties | Office Building
Real Estate Properties [Line Items]
Number of real estate properties		10
Unconsolidated Properties | Office Building
Real Estate Properties [Line Items]
Number of real estate properties		9
Columbia Operating Partnership
Real Estate Properties [Line Items]
General partner and majority owner, percentage		97.30%
Terminal Warehouse Joint Venture | Corporate Joint Venture
Real Estate Properties [Line Items]
General partner and majority owner, percentage	33.00%
Square feet of real estate | ft²	1,200,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details)	3 Months Ended
	Mar. 31, 2021USD ($)investmentinterest_rate_swapproperty	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)property
Property, Plant and Equipment [Line Items]
Capitalized interest costs	$ 2,800,000	$ 2,600,000
Number of properties held-for-sale | property	0		0
Write-off of tenant receivables	$ 1,340,000	8,000
Write-off of straight-line rent receivables	200,000
Hedge ineffectiveness recognized in earnings	0	0
Strategic review costs	$ 2,356,000	0
Requirement to distribute taxable income (at least)	90.00%
Limit on investments in taxable real estate investment trusts (percent)	20.00%
Real Estate Funds
Property, Plant and Equipment [Line Items]
Carrying Value of Investment	$ 4,200,000		$ 4,300,000
Unrealized loss on investments in real estate funds	$ 200,000	200,000
Real Estate Funds | Normandy
Property, Plant and Equipment [Line Items]
Number of real estate funds | investment	3
Minimum | Real Estate Funds | Normandy
Property, Plant and Equipment [Line Items]
Economic interest percentage	2.00%
Maximum | Real Estate Funds | Normandy
Property, Plant and Equipment [Line Items]
Economic interest percentage	2.50%
Building
Property, Plant and Equipment [Line Items]
Estimated useful life of real estate assets	40 years
Building and site improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of real estate assets	5 years
Building and site improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of real estate assets	25 years
Interest Rate Swap
Property, Plant and Equipment [Line Items]
Number of derivative instruments held | interest_rate_swap	2
Notional amount	$ 450,000,000
Corporate Joint Venture
Property, Plant and Equipment [Line Items]
Capitalized interest costs	800,000	$ 400,000
Carrying Value of Investment	$ 1,295,419,000		$ 1,295,800,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Schedule of Intangible Assets & Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Gross Intangible In-Place Lease Assets and Liabilities [Abstract]
Intangible Lease Assets, Accumulated Amortization	$ (57,970)	$ (57,947)
Intangible lease assets, net	43,663	46,075
Intangible Lease Origination Costs, Accumulated Amortization	(35,662)	(35,161)
Intangible Lease Origination Costs, Net	20,152	21,451
Below Market Lease, Gross	21,281	23,287
Below Market Lease, Accumulated Amortization	(7,582)	(8,867)
Below Market Lease, Net	13,699	14,420
Above-Market In-Place Lease Assets
Gross Intangible In-Place Lease Assets and Liabilities [Abstract]
Intangible Lease Assets, Gross	2,480	2,480
Intangible Lease Assets, Accumulated Amortization	(1,416)	(1,374)
Intangible lease assets, net	1,064	1,106
Absorption Period Costs
Gross Intangible In-Place Lease Assets and Liabilities [Abstract]
Intangible Lease Assets, Gross	99,153	101,542
Intangible Lease Assets, Accumulated Amortization	(56,554)	(56,573)
Intangible lease assets, net	42,599	44,969
Intangible Lease Origination Costs
Gross Intangible In-Place Lease Assets and Liabilities [Abstract]
Intangible Lease Origination Costs, Gross	55,814	56,612
Intangible Lease Origination Costs, Accumulated Amortization	(35,662)	(35,161)
Intangible Lease Origination Costs, Net	$ 20,152	$ 21,451

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Schedule of Recognized Amortization) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Lease Assets	$ 4,844	$ 6,721
Intangible Below-Market In-Place Lease Liabilities	722	1,596
Above-Market In-Place Lease Assets
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Lease Assets	42	43
Absorption Period Costs
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Lease Assets	2,369	3,700
Intangible Lease Origination Costs
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Lease Assets	$ 1,299	$ 1,586

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Schedule of Future Amortization by Intangible Asset Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
For the Years Ending December 31:
Intangible lease assets, net	$ 43,663	$ 46,075
Intangible Lease Origination Costs, Net	20,152	21,451
Intangible Below-Market In-Place Lease Liabilities
For the remainder of 2021	2,080
For the years ending December 31:
2022	2,571
2023	1,995
2024	1,748
2025	1,182
2026	964
Thereafter	3,159
Below Market Lease, Net	13,699	14,420
Above-Market In-Place Lease Assets
Finite-Lived Intangible Assets [Line Items]
For the remainder of 2021	129
For the Years Ending December 31:
2022	172
2023	172
2024	172
2025	172
2026	109
Thereafter	138
Intangible lease assets, net	1,064	1,106
Absorption Period Costs
Finite-Lived Intangible Assets [Line Items]
For the remainder of 2021	6,594
For the Years Ending December 31:
2022	7,620
2023	6,138
2024	5,333
2025	3,943
2026	2,832
Thereafter	10,139
Intangible lease assets, net	42,599	44,969
Intangible Lease Origination Costs
Finite-Lived Intangible Assets [Line Items]
For the remainder of 2021	3,111
For the Years Ending December 31:
2022	3,335
2023	2,810
2024	2,500
2025	1,849
2026	1,321
Thereafter	5,226
Intangible Lease Origination Costs, Net	$ 20,152	$ 21,451

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Interest Rate Swaps) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Summary of Derivative Instruments Impact on Results of Operations [Abstract]
Market value adjustments to interest rate swaps that qualify for hedge accounting treatment	$ 4,624	$ (19,993)
Interest rate contracts | Accounts payable
Derivative, Fair Value, Net [Abstract]
Derivative designated as hedging instruments	$ 14,096		$ 18,720

Transactions (Acquisitions Narr

Transactions (Acquisitions Narrative) (Details)	Mar. 13, 2020USD ($)ft²	Jan. 24, 2020USD ($)$ / sharesshares	Apr. 29, 2021option	Mar. 31, 2021USD ($)ft²option	Sep. 30, 2020USD ($)	Mar. 31, 2020USD ($)
Business Acquisition [Line Items]
Square feet of real estate | ft²				6,200,000
Corporate Joint Venture | Terminal Warehouse Joint Venture
Business Acquisition [Line Items]
Economic interest	8.65%			8.65%
Purchase price	$ 40,000,000
Square feet of real estate | ft²	1,200,000
Debt term	2 years
Maximum borrowing capacity	$ 650,000,000
Outstanding balance				$ 645,500,000
Number of extension options | option				2
Extension term				8 months
General partner and majority owner, percentage	33.00%
Corporate Joint Venture | Terminal Warehouse Joint Venture | Subsequent Event
Business Acquisition [Line Items]
Number of extension options | option			2
Extension term			8 months
Normandy Acquisition
Business Acquisition [Line Items]
Cash payment		$ 14,000,000
Goodwill		$ 63,806,000
Transaction costs related to acquisition						$ 12,100,000
Additional revenue since acquisition date					$ 5,200,000
Net income since acquisition date					$ 700,000
Normandy Acquisition | Preferred OP Units
Business Acquisition [Line Items]
Number of shares to be issued for acquisition (in shares) | shares		3,264,151
Liquidation preference (in dollars per share) | $ / shares		$ 26.50
Estimated fair value (in dollars per share) | $ / shares		$ 24.43

Transactions (Purchase Price Al

Transactions (Purchase Price Allocation) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)	Jan. 24, 2020USD ($)joint_venture
Business Acquisition [Line Items]
Total initial purchase consideration		$ 70,197
Normandy Acquisition
Business Acquisition [Line Items]
Goodwill		63,806
Prepaid expenses and other assets		7,670
Cash		1,260
Operating lease assets		934
Investments in unconsolidated joint ventures		419
Accounts payable, accrued expenses, and accrued capital expenditures		(2,881)
Operating lease liabilities		(934)
Deferred income		(77)
Impairment loss on goodwill	$ 63,800
Investments in real estate funds		$ 3,700
Number of unconsolidated joint ventures | joint_venture		5

Transactions (Dispositions) (De

Transactions (Dispositions) (Details) - Disposed of by Sale - USD ($) $ in Thousands	Oct. 08, 2020	Mar. 31, 2020	Jan. 16, 2020	Mar. 31, 2020	Sep. 30, 2020
221 Main Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% Sold	45.00%
Sales Price	$ 180,000
Gain (loss) on sale	$ 175,271
Pasadena Corporate Park
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% Sold		100.00%		100.00%
Sales Price		$ 78,000		$ 78,000	$ 78,000
Gain (loss) on sale		$ (67)		$ (67)
Cranberry Woods Drive
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% Sold			100.00%
Sales Price			$ 180,000
Gain (loss) on sale			$ 13,428

Transactions (Dispositions Narr

Transactions (Dispositions Narrative) (Details) - USD ($) $ in Thousands	Oct. 08, 2020	Mar. 31, 2020	Jan. 16, 2020	Mar. 31, 2020	Dec. 31, 2019	Oct. 09, 2020	Sep. 30, 2020
221 Main Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership Interest						55.00%
Disposed of by Sale | 221 Main Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% Sold	45.00%
Sales Price	$ 180,000
Gain (loss) on sale	175,271
Disposed of by Sale | 221 Main Street Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on sale	$ 175,300
Disposed of by Sale | Pasadena Corporate Park
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% Sold		100.00%		100.00%
Sales Price		$ 78,000		$ 78,000			$ 78,000
Gain (loss) on sale		$ (67)		$ (67)
Impairment loss on real estate assets					$ 20,600
Disposed of by Sale | Cranberry Woods Drive
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
% Sold			100.00%
Sales Price			$ 180,000
Gain (loss) on sale			$ 13,428

Unconsolidated Joint Ventures_2

Unconsolidated Joint Ventures (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)joint_venture	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Schedule of Equity Method Investments [Line Items]
Interest capitalized	$ 3,600
Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Carrying Value of Investment	$ 1,295,419		$ 1,295,800
Corporate Joint Venture | Unconsolidated Properties | L&L Normandy Terminal Asset Manager, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	67.00%
Corporate Joint Venture | Unconsolidated Properties | L&L Normandy Terminal Development Manager, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	50.00%
Corporate Joint Venture | Unconsolidated Properties | L&L Normandy Terminal Property Manager
Schedule of Equity Method Investments [Line Items]
Ownership Interest	50.00%
Corporate Joint Venture | Unconsolidated Properties | WNK Maiden Management
Schedule of Equity Method Investments [Line Items]
Ownership Interest	50.00%
Corporate Joint Venture | Unconsolidated Properties | Maple AB Services, LLC
Schedule of Equity Method Investments [Line Items]
Ownership Interest	55.00%
Corporate Joint Venture | University Circle Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	55.00%
Carrying Value of Investment	$ 275,867		276,574
Corporate Joint Venture | 333 Market Street Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	55.00%
Carrying Value of Investment	$ 264,483		265,673
Corporate Joint Venture | 1800 M Street Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	55.00%
Carrying Value of Investment	$ 225,888		227,847
Corporate Joint Venture | 221 Main Street Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	55.00%
Carrying Value of Investment	$ 217,057		219,078
Corporate Joint Venture | 114 Fifth Avenue Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	49.50%
Carrying Value of Investment	$ 75,367		74,273
Corporate Joint Venture | Market Square Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	51.00%
Carrying Value of Investment	$ 133,726		134,747
Corporate Joint Venture | 799 Broadway Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	49.70%
Carrying Value of Investment	$ 55,888		53,248
Interest capitalized	$ 800	$ 300
Corporate Joint Venture | Terminal Warehouse Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership Interest	8.65%
Carrying Value of Investment	$ 46,571		43,771
Corporate Joint Venture | Real Estate Services Joint Ventures
Schedule of Equity Method Investments [Line Items]
Carrying Value of Investment	$ 572		589
Corporate Joint Venture | Real Estate Services Joint Ventures | Unconsolidated Properties
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated joint ventures | joint_venture	5
Corporate Joint Venture | Market Square, University Circle, 333 Market Street, 114 Fifth Avenue, 1800 M Street, 799 Broadway Joint Ventures And Terminal Warehouse
Schedule of Equity Method Investments [Line Items]
Aggregate basis difference	$ 382,100		$ 383,500

Unconsolidated Joint Ventures_3

Unconsolidated Joint Ventures (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)joint_venture	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Related Party Transaction [Line Items]
Number of joint ventures that qualify as variable interest entities | joint_venture	2
Property operating costs
Related Party Transaction [Line Items]
Reimbursements of property operating costs	$ 10,079	$ 8,240
Property operating costs | Other property income
Related Party Transaction [Line Items]
Reimbursements of property operating costs	1,400	$ 1,300
Prepaid expenses and other assets | Corporate Joint Venture
Related Party Transaction [Line Items]
Property management fee receivable	$ 500		$ 400

Unconsolidated Joint Ventures_4

Unconsolidated Joint Ventures (Condensed Balance Sheet Information for Joint Ventures) (Details)	3 Months Ended
	Mar. 31, 2021USD ($)optionextension	Dec. 31, 2020USD ($)	Mar. 31, 2020USD ($)	Mar. 13, 2020USD ($)	Dec. 31, 2019USD ($)
Schedule of Equity Method Investments [Line Items]
Total Assets	$ 4,049,392,000	$ 4,086,518,000
Total Debt	1,383,133,000	1,402,924,000
Total Equity	2,666,259,000	2,683,594,000	$ 2,624,387,000		$ 2,628,617,000
Deferred financing costs, net	$ 1,316,000	1,470,000
Corporate Joint Venture | Terminal Warehouse Joint Venture
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity				$ 650,000,000
Extension term	8 months
Number of extension options | option	2
Corporate Joint Venture | Blackstone Property Partners
Schedule of Equity Method Investments [Line Items]
Debt	$ 325,000,000
Mortgage note interest rate	5.07%
Corporate Joint Venture | 799 Broadway Joint Venture
Schedule of Equity Method Investments [Line Items]
Amount borrowed under construction loan	$ 145,100,000
Deferred financing costs, net	$ 1,000,000
LIBOR (minimum)	1.00%
LIBOR (maximum)	4.00%
Extension term	1 year
Corporate Joint Venture | 799 Broadway Joint Venture | Construction loan
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	$ 187,000,000
Number of extensions available | extension	2
Corporate Joint Venture | 799 Broadway Joint Venture | LIBOR
Schedule of Equity Method Investments [Line Items]
Basis spread	4.25%
Corporate Joint Venture | Terminal Warehouse Joint Venture
Schedule of Equity Method Investments [Line Items]
Amount borrowed under construction loan	$ 645,500,000
Deferred financing costs, net	$ 400,000
LIBOR (minimum)	2.28%
LIBOR (maximum)	3.50%
Corporate Joint Venture | Terminal Warehouse Joint Venture | Construction loan
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	$ 650,000,000
Corporate Joint Venture | Terminal Warehouse Joint Venture | LIBOR
Schedule of Equity Method Investments [Line Items]
Basis spread	3.40%
Corporate Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	$ 3,589,448,000	3,561,238,000
Total Debt	1,114,078,000	1,107,617,000
Total Equity	2,033,974,000	2,009,444,000
Corporate Joint Venture | University Circle Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	214,280,000	213,045,000
Total Debt	0	0
Total Equity	208,653,000	208,541,000
Corporate Joint Venture | 333 Market Street Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	354,835,000	357,370,000
Total Debt	0	0
Total Equity	341,676,000	344,103,000
Corporate Joint Venture | 1800 M Street Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	421,219,000	427,602,000
Total Debt	0	0
Total Equity	408,417,000	411,957,000
Corporate Joint Venture | 221 Main Street Joint Venture
Schedule of Equity Method Investments [Line Items]
Total Assets	230,231,000	229,745,000
Total Debt	0	0
Total Equity	224,523,000	224,732,000
Corporate Joint Venture | 114 Fifth Avenue Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	464,030,000	462,319,000
Total Debt	0	0
Total Equity	104,567,000	101,952,000
Corporate Joint Venture | Market Square Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	568,545,000	577,095,000
Total Debt	324,881,000	324,868,000
Total Equity	235,187,000	237,778,000
Corporate Joint Venture | 799 Broadway Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	255,670,000	246,456,000
Total Debt	144,116,000	138,930,000
Total Equity	103,249,000	99,000,000
Corporate Joint Venture | Terminal Warehouse Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	1,079,057,000	1,045,852,000
Total Debt	645,081,000	643,819,000
Total Equity	406,725,000	380,277,000
Corporate Joint Venture | Real Estate Services Joint Ventures | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Assets	1,581,000	1,754,000
Total Debt	0	0
Total Equity	$ 977,000	$ 1,104,000

Unconsolidated Joint Ventures_5

Unconsolidated Joint Ventures (Condensed Income Statement Information for the Joint Ventures) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule of Equity Method Investments [Line Items]
Total Revenues	$ 64,388	$ 76,254
Net Income (Loss)	445	6,228
Corporate Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	62,447	55,228
Net Income (Loss)	15,879	3,690
Columbia Property Trust's Share of Net Income (Loss)	9,494	3,815
Corporate Joint Venture | University Circle Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	10,305	10,924
Net Income (Loss)	5,112	5,715
Columbia Property Trust's Share of Net Income (Loss)	2,811	3,144
Corporate Joint Venture | 333 Market Street Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	7,135	7,067
Net Income (Loss)	3,672	3,705
Columbia Property Trust's Share of Net Income (Loss)	2,020	2,037
Corporate Joint Venture | 1800 M Street Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	9,631	9,937
Net Income (Loss)	1,463	1,752
Columbia Property Trust's Share of Net Income (Loss)	805	964
Corporate Joint Venture | 221 Main Street Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	7,982	0
Net Income (Loss)	2,583	0
Columbia Property Trust's Share of Net Income (Loss)	1,420	0
Corporate Joint Venture | Market Square Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	12,597	12,690
Net Income (Loss)	(2,586)	(1,994)
Columbia Property Trust's Share of Net Income (Loss)	(1,319)	(1,017)
Corporate Joint Venture | 114 Fifth Avenue Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	10,735	10,428
Net Income (Loss)	6,865	(2,653)
Columbia Property Trust's Share of Net Income (Loss)	3,398	(1,314)
Corporate Joint Venture | 799 Broadway Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	0	0
Net Income (Loss)	(40)	(32)
Columbia Property Trust's Share of Net Income (Loss)	(20)	(16)
Corporate Joint Venture | Terminal Warehouse Joint Venture | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	2,173	2,307
Net Income (Loss)	(2,152)	(3,741)
Columbia Property Trust's Share of Net Income (Loss)	(186)	(324)
Corporate Joint Venture | Real Estate Services Joint Ventures | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Total Revenues	1,889	1,875
Net Income (Loss)	962	938
Columbia Property Trust's Share of Net Income (Loss)	$ 565	$ 341

Unconsolidated Joint Ventures_6

Unconsolidated Joint Ventures (Management Fees) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	$ 4,500	$ 4,300
Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	2,434	2,153
University Circle Joint Venture | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	587	587
333 Market Street Joint Venture | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	209	214
1800 M Street Joint Venture | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	562	555
221 Main Street Joint Venture | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	471	0
Market Square Joint Venture | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	605	574
799 Broadway Joint Venture | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Asset and property management fees	$ 0	$ 223

Line of Credit and Notes Paya_3

Line of Credit and Notes Payable (Schedule of Long-Term Debt (excluding Bonds Payable)) (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Loan payable	$ 572,684,000	$ 558,530,000
Less: Deferred financing costs related to term loans and notes payable, net of accumulated amortization	(1,316,000)	(1,470,000)
Term Loans
Debt Instrument [Line Items]
Less: Deferred financing costs related to term loans and notes payable, net of accumulated amortization	(1,316,000)	(1,470,000)
Term Loans | $300 Million Term Loan
Debt Instrument [Line Items]
Face amount of issued debt instrument	300,000,000	300,000,000
Loan payable	300,000,000	300,000,000
Term Loans | $150 Million Term Loan
Debt Instrument [Line Items]
Face amount of issued debt instrument	150,000,000	150,000,000
Loan payable	150,000,000	150,000,000
Credit Facilities | Revolving Credit Facility
Debt Instrument [Line Items]
Loan payable	$ 124,000,000	$ 110,000,000

Line of Credit and Notes Paya_4

Line of Credit and Notes Payable (Narrative) (Details)	3 Months Ended
	Mar. 31, 2021USD ($)extension	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Interest payments	$ 3,700,000	$ 5,000,000
Interest capitalized	3,600,000
Capitalized interest costs	$ 2,800,000	2,600,000
Weighted average interest rate	3.23%
Corporate Joint Venture
Debt Instrument [Line Items]
Capitalized interest costs	$ 800,000	400,000
Term Loans | $300 Million Term Loan
Debt Instrument [Line Items]
Face amount of issued debt instrument	$ 300,000,000		$ 300,000,000
Term Loans | $300 Million Term Loan | Interest Rate Swap
Debt Instrument [Line Items]
Effective interest rate	2.55%
Term Loans | $300 Million Term Loan | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread	0.00%
Term Loans | $300 Million Term Loan | Minimum | LIBOR
Debt Instrument [Line Items]
Basis spread	0.85%
Term Loans | $300 Million Term Loan | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread	0.65%
Term Loans | $300 Million Term Loan | Maximum | LIBOR
Debt Instrument [Line Items]
Basis spread	1.65%
Term Loans | $150 Million Term Loan
Debt Instrument [Line Items]
Face amount of issued debt instrument	$ 150,000,000		150,000,000
Term Loans | $150 Million Term Loan | Interest Rate Swap
Debt Instrument [Line Items]
Effective interest rate	3.07%
Term Loans | $150 Million Term Loan | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread	0.00%
Term Loans | $150 Million Term Loan | Minimum | LIBOR
Debt Instrument [Line Items]
Basis spread	0.90%
Term Loans | $150 Million Term Loan | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread	0.75%
Term Loans | $150 Million Term Loan | Maximum | LIBOR
Debt Instrument [Line Items]
Basis spread	1.75%
Credit Facilities
Debt Instrument [Line Items]
Term of extension	1 year
Credit Facilities | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 650,000,000
Number of possible extensions | extension	2
Term of extension	6 months
Credit Facilities | Revolving Credit Facility | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread	0.00%
Credit Facilities | Revolving Credit Facility | Minimum | LIBOR
Debt Instrument [Line Items]
Basis spread	0.775%
Credit Facilities | Revolving Credit Facility | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread	0.45%
Credit Facilities | Revolving Credit Facility | Maximum | LIBOR
Debt Instrument [Line Items]
Basis spread	1.45%
Loans Payable
Debt Instrument [Line Items]
Estimated fair value of line of credit and notes payable	$ 578,000,000		564,600,000
Carrying value of the line of credit and notes payable	$ 574,000,000		$ 560,000,000
Interest capitalized		3,000,000
Capitalized interest costs		$ 2,600,000

Bonds Payable (Details)

Bonds Payable (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2021USD ($)bond	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)bond
Debt Instrument [Line Items]
Number of series of bonds | bond	2		2
Interest payments	$ 3,700,000	$ 5,000,000
Carrying value, net of discounts	696,301,000		$ 696,103,000
Bonds Payable | 2026 and 2025 Bonds Payable
Debt Instrument [Line Items]
Interest payments	6,400,000	$ 6,400,000
Bonds Payable | 2026 and 2025 Bonds Payable | Level 2
Debt Instrument [Line Items]
Estimated fair value of debt instrument	755,100,000		738,200,000
Carrying value, net of discounts			699,100,000
Bonds Payable | 2026 Bonds Payable
Debt Instrument [Line Items]
Face amount of issued debt instrument	$ 350,000,000		$ 350,000,000
Maturity of debt instrument	10 years		10 years
Interest rate for debt instrument (percent)	3.65%		3.65%
Discount rate of face value of issued debt instrument (percent)	99.626%		99.626%
Bonds Payable | 2025 Bonds Payable
Debt Instrument [Line Items]
Face amount of issued debt instrument	$ 350,000,000		$ 350,000,000
Maturity of debt instrument	10 years		10 years
Interest rate for debt instrument (percent)	4.15%		4.15%
Discount rate of face value of issued debt instrument (percent)	99.859%		99.859%

Commitments and Contingencies (

Commitments and Contingencies (Details)	3 Months Ended
	Mar. 31, 2021USD ($)property
Loss Contingencies [Line Items]
Unfunded capital contributions	$ 3,800,000
Corporate Joint Venture | 799 Broadway Joint Venture
Loss Contingencies [Line Items]
Construction loan guaranty	6,800,000
Capital calls unpaid	0
Guaranty liability	0
Corporate Joint Venture | 799 Broadway Joint Venture
Loss Contingencies [Line Items]
Amount borrowed under construction loan	145,100,000
Corporate Joint Venture | Columbia Property Trust and joint venturer | 799 Broadway Joint Venture
Loss Contingencies [Line Items]
Construction loan guaranty	$ 13,700,000
Office Building
Loss Contingencies [Line Items]
Number of real estate properties | property	15
Office Building | Corporate Joint Venture
Loss Contingencies [Line Items]
Number of real estate properties | property	9
Properties Under Development or Redevelopment | Corporate Joint Venture
Loss Contingencies [Line Items]
Number of real estate properties | property	3
80 M Street | Capital Addition Purchase Commitments
Loss Contingencies [Line Items]
Purchase commitment	$ 42,500,000
95 Columbus
Loss Contingencies [Line Items]
Unrecorded tenant commitments	$ 25,200,000

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 04, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to unvested awards	$ 20,400,000	$ 12,400,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs recognition period (years)	1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs recognition period (years)	4 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (shares)	430,000
Preferred OP Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested unit awards	$ 8,500,000	$ 10,300,000
Preferred OP Unit Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs recognition period (years)	3 years
Preferred OP Unit Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs recognition period (years)	4 years
2013 Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	4,800,000
Long Term Incentive Plan | Time-based Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (shares)	421,962
Vesting period	4 years
Long Term Incentive Plan | RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (shares)	429,977
Performance period	3 years
Long Term Incentive Plan | RSUs | End of Performance Period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (percent)	75.00%
Long Term Incentive Plan | RSUs | 1 Year Post Performance Period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights (percent)	25.00%
Common Stock | 2017 Stock Repurchase Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount			$ 200,000,000
Stock repurchase program, amount available for repurchase	$ 143,300,000
Common Stock | 2019 Stock Repurchase Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate purchases (in shares)	0

Stockholders' Equity (Unvested

Stockholders' Equity (Unvested Activity Rollforward) (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2021$ / sharesshares
Weighted-Average, Grant-Date Fair Value Rollforward
Expected forfeiture rate	4.50%
Restricted Shares
Shares Rollforward
Unvested awards - beginning of period (shares)	497
Granted (shares)	422
Converted (shares)	24
Vested (shares)	(195)
Forfeited (shares)	(2)
Unvested awards - end of period (shares)	746
Weighted-Average, Grant-Date Fair Value Rollforward
Unvested awards - beginning of period (dollars per share) | $ / shares	$ 20.82
Granted (dollars per share) | $ / shares	14.33
Vested (dollars per share) | $ / shares	21.32
Forfeited (dollars per share) | $ / shares	14.34
Unvested awards - end of period (dollars per share) | $ / shares	$ 15.75
Performance period	3 years
Shares expected to ultimately vest (shares)	712
RSUs
Shares Rollforward
Unvested awards - beginning of period (shares)	715
Granted (shares)	430
Converted (shares)	(24)
Vested (shares)	(73)
Forfeited (shares)	(1)
Unvested awards - end of period (shares)	1,047
Weighted-Average, Grant-Date Fair Value Rollforward
Unvested awards - beginning of period (dollars per share) | $ / shares	$ 18.51
Granted (dollars per share) | $ / shares	12.39
Vested (dollars per share) | $ / shares	20.66
Forfeited (dollars per share) | $ / shares	12.39
Unvested awards - end of period (dollars per share) | $ / shares	$ 15.16
Shares expected to ultimately vest (shares)	1,000

Stockholders' Equity (Director

Stockholders' Equity (Director Stock Grants) (Details) - Director - $ / shares	Jan. 04, 2021	Mar. 02, 2020
January,4, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted	582
Grant-Date Fair Value (dollars per share)	$ 14.24
March 2, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		591
Grant-Date Fair Value (dollars per share)		$ 19.80

Stockholders' Equity (Stock-bas

Stockholders' Equity (Stock-based Compensation Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	$ 4,144	$ 4,657
Amortization of performance-based awards	1,143	1,031
Amortization of Preferred OP unit awards issued in connection with the Normandy Acquisition	1,832	2,358
Total stock-based compensation expense	4,145	4,348
Employees
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	1,024	947
Director
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock based compensation expense	$ 146	$ 12

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) $ / shares in Units, ft² in Thousands, $ in Thousands	Jan. 24, 2020property$ / sharesshares	Mar. 31, 2021USD ($)ft²shares	Dec. 31, 2020USD ($)
Noncontrolling Interest [Line Items]
Total assets		$ 4,049,392	$ 4,086,518
Total liabilities		$ 1,383,133	$ 1,402,924
Square feet of real estate | ft²		6,200
Columbia Operating Partnership
Noncontrolling Interest [Line Items]
Total assets		$ 3,900,000
Total liabilities		$ 1,500,000
Columbia Operating Partnership | Variable Interest Entity, Primary Beneficiary
Noncontrolling Interest [Line Items]
Variable interest entity percentage		97.30%
101 Franklin Street
Noncontrolling Interest [Line Items]
Total assets		$ 4,900
Total liabilities		$ 10,000
Square feet of real estate | ft²		235
101 Franklin Street | Variable Interest Entity, Primary Beneficiary
Noncontrolling Interest [Line Items]
Variable interest entity percentage		92.50%
101 Franklin Street | Variable Interest Entity, Primary Beneficiary | Normandy Real Estate Fund IV, L.P.
Noncontrolling Interest [Line Items]
Variable interest entity percentage		0.15%
Preferred OP Units
Noncontrolling Interest [Line Items]
Conversion rate of Preferred OP Units | property	1
Preferred OP Units | Minimum
Noncontrolling Interest [Line Items]
Vesting period	3 years
Preferred OP Units | Maximum
Noncontrolling Interest [Line Items]
Vesting period	4 years
Preferred OP Units | Normandy Acquisition
Noncontrolling Interest [Line Items]
Number of shares to be issued for acquisition (in shares) | shares	3,264,151
Liquidation preference (in dollars per share) | $ / shares	$ 26.50
Preferred units repurchased (in shares) | shares		19,700

Supplemental Disclosures of N_3

Supplemental Disclosures of Noncash Investing and Financing Activities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Other assets assumed at acquisition	$ 0	$ 245
Operating lease asset and liability assumed at acquisition	0	961
Other liabilities assumed at acquisition	0	245
Amortization of net discounts on debt	45	45
Accrued capital expenditures and deferred lease costs	14,057	15,447
Market value adjustments to interest rate swaps that qualify for hedge accounting treatment	4,624	(19,993)
Issuance of Preferred OP Units for the Normandy Acquisition (Note 3)	0	55,306
Stock-based compensation expense	$ 4,144	$ 4,348

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)leaseground_lease	Dec. 31, 2020USD ($)
Lessee, Lease, Description [Line Items]
Operating lease, number of ground leases | ground_lease	1
Number of office leases | lease	2
Operating lease assets	$ 38,737	$ 39,165
Operating lease liabilities	$ 1,801	$ 2,185
Lessor, operating lease, weighted-average remaining lease term	5 years 10 months 24 days
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	98 years 4 months 24 days
Maximum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, liability, term of contract	1 year 7 months 6 days

Leases - Fixed and Variable Rev

Leases - Fixed and Variable Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Fixed payments	$ 47,690	$ 61,243
Variable payments	6,619	6,764
Total lease revenues	$ 54,309	$ 68,007

Non-Lease Revenues (Details)

Non-Lease Revenues (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Asset and property management fee income	$ 4,500,000	$ 4,300,000
Leasing override fee income	48,400	14,600
Construction and development fees	$ 300,000	800,000
Salary and other reimbursement revenue, recognition period, one	1 month
Salary and other reimbursement revenue, recognition period, two	3 months
Salary and other reimbursement revenue, recognition period, three	1 year
Salary and other reimbursement revenue	$ 4,000,000	3,100,000
Miscellaneous revenue	$ 0	$ 7,100
Maximum
Disaggregation of Revenue [Line Items]
Management fee revenue, recognition period	3 months
Miscellaneous revenue, recognition period	3 months
Minimum
Disaggregation of Revenue [Line Items]
Miscellaneous revenue, recognition period	1 month

Earnings Per Share (Basic and D

Earnings Per Share (Basic and Diluted EPS Computations) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 445	$ 6,228
Net Income (Loss) Attributable to Noncontrolling Interest	(97)	(71)
Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Redeemable	129	133
Net income attributable to common stockholders	477	6,290
Distributions paid on unvested shares	(157)	(113)
Net income (loss) attributable to common stockholders used to calculate basic earnings per share	320	6,177
Net income attributable to noncontrolling interest in Columbia OP	97	71
Net income (loss) attributable to common stockholder and Columbia OP Unit-holders used to calculate diluted earnings per share	$ 417	$ 6,248
Weighted-average common shares – basic	114,115,000	114,471,000
Weighted-average common shares – diluted, before adjustment for OP Units	114,607,000	114,486,000
Weighted-average common shares – diluted	117,851,000	114,486,000
Anti-dilutive shares	37,400	0
Previously granted awards, unvested
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Plus incremental weighted-average shares from time-vested conversions, less assumed stock repurchases	0	15,000
Future period LTI Plan awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Plus incremental weighted-average shares from time-vested conversions, less assumed stock repurchases	492,000	0
Convertible Preferred OP Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Plus incremental weighted-average shares from time-vested conversions, less assumed stock repurchases	3,244,000	2,367,000

Segment Information (Operating

Segment Information (Operating Revenues by Geographic Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Oct. 07, 2020	Mar. 13, 2020
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	$ 87,072	$ 97,287
Operating revenues	64,388	76,254
Management fee revenues	(4,500)	(4,300)
Corporate Joint Venture
Segment Reporting Information [Line Items]
Management fee revenues	$ (2,434)	(2,153)
Corporate Joint Venture | Terminal Warehouse Joint Venture
Segment Reporting Information [Line Items]
Economic interest	8.65%			8.65%
114 Fifth Avenue Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	49.50%
333 Market Street and University Circle | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	55.00%		100.00%
Market Square Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	51.00%
Management fee revenues	$ (605)	(574)
1800 M Street Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	55.00%
Management fee revenues	$ (562)	(555)
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	87,655	97,660
Operating Segments | New York
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	40,129	41,105
Operating Segments | San Francisco
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	29,125	34,801
Operating Segments | Washington, D.C.
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	14,432	15,018
Operating Segments | Boston
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	3,969	4,149
Operating Segments | All other office markets
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	0	2,587
Corporate
Segment Reporting Information [Line Items]
Operating revenues including unconsolidated joint venture	(583)	(373)
Eliminations
Segment Reporting Information [Line Items]
Operating revenues	32,763	29,273
Management fee revenues	$ (10,079)	$ (8,240)

Segment Information (Net Operat

Segment Information (Net Operating Income By Geographic Reportable Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Oct. 07, 2020	Mar. 13, 2020
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	$ 57,214	$ 63,009
Corporate Joint Venture | Terminal Warehouse Joint Venture
Segment Reporting Information [Line Items]
Economic interest	8.65%			8.65%
114 Fifth Avenue Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	49.50%
799 Broadway Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	49.70%
333 Market Street and University Circle | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	55.00%		100.00%
Market Square Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	51.00%
1800 M Street Joint Venture | Corporate Joint Venture
Segment Reporting Information [Line Items]
Ownership percentage	55.00%
Operating Segments
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	$ 57,711	63,281
Operating Segments | New York
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	27,417	25,075
Operating Segments | San Francisco
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	19,939	25,072
Operating Segments | Washington, D.C.
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	8,169	9,151
Operating Segments | Boston
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	2,186	2,458
Operating Segments | All other office markets
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	0	1,525
Corporate
Segment Reporting Information [Line Items]
Net operating income (loss) including unconsolidated joint venture	$ (497)	$ (272)

Segment Information (Reconcilia

Segment Information (Reconciliation of GAAP Net Income to NOI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Net income attributable to common stockholders	$ 477	$ 6,290
Management fee revenues	(4,500)	(4,300)
Depreciation	16,531	18,330
General and administrative	9,776	11,782
Strategic review costs	2,356	0
Management fee expenses	9,269	6,945
Acquisition costs	0	12,081
Income tax expense (benefit)	(329)	(2,243)
Gain on sale of real estate assets	0	(13,344)
Adjustments attributable to noncontrolling interests	97	71
NOI	57,214	63,009
Segment Reconciling Items
Segment Reporting Information [Line Items]
Management fee revenues	(10,079)	(8,240)
Depreciation	16,531	18,330
Amortization	4,844	6,721
General and administrative	9,776	11,782
Management fee expenses	9,269	6,945
Acquisition costs	0	12,081
Net interest expense	7,535	9,553
Market value adjustments to investment in Real Estate Funds	239	160
Income tax expense (benefit)	(329)	(2,243)
Adjustments included in income from unconsolidated joint ventures	16,627	14,903
Gain on sale of real estate assets	0	(13,344)
Adjustments attributable to noncontrolling interests	$ (32)	$ 71