Franklin Street Properties (FSP) 10-K 15 Feb 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 04, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2021
Entity File Number	001-32470
Entity Registrant Name	FRANKLIN STREET PROPERTIES CORP.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	04-3578653
Entity Address, Address Line One	401 Edgewater Place, Suite 200
Entity Address, City or Town	Wakefield
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01880
City Area Code	781
Local Phone Number	557-1300
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 537,721,714
Title of 12(b) Security	Common Stock
Trading Symbol	FSP
Security Exchange Name	NYSEAMER
Entity Common Stock, Shares Outstanding		103,998,520
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001031316
Amendment Flag	false
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Boston, Massachusetts

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Real estate assets:
Land	$ 146,844	$ 189,155
Buildings and improvements	1,457,209	1,938,629
Fixtures and equipment	11,404	12,949
Total real estate assets, gross	1,615,457	2,140,733
Less accumulated depreciation	424,487	538,717
Real estate assets, net	1,190,970	1,602,016
Acquired real estate leases, less accumulated amortization of $40,423 and $55,447, respectively	14,934	28,206
Cash, cash equivalents and restricted cash	40,751	4,150
Tenant rent receivables	1,954	7,656
Straight-line rent receivable	49,024	67,789
Prepaid expenses and other assets	4,031	5,752
Related party mortgage loan receivable	24,000	21,000
Office computers and furniture, net of accumulated depreciation of $1,198 and $1,443, respectively	198	163
Deferred leasing commissions, net of accumulated amortization of $21,099 and $30,411, respectively	38,311	56,452
Total assets	1,364,173	1,793,184
Liabilities:
Bank note payable		3,500
Term loans payable, less unamortized financing costs of $714 and $2,677, respectively	274,286	717,323
Series A & Series B Senior Notes, less unamortized financing costs of $658 and $822, respectively	199,342	199,178
Accounts payable and accrued expenses	89,493	72,058
Accrued compensation	4,704	3,918
Tenant security deposits	6,219	8,677
Lease liability	1,159	1,536
Other liabilities: derivative liabilities	5,239	17,311
Acquired unfavorable real estate leases, less accumulated amortization of $2,285 and $4,031, respectively	528	1,592
Total liabilities	580,970	1,025,093
Commitments and contingencies
Stockholders' Equity:
Preferred stock, $.0001 par value, 20,000,000 shares authorized, none issued or outstanding
Common stock, $.0001 par value, 180,000,000 shares authorized, 103,998,520 and 107,328,199 shares issued and outstanding, respectively	10	11
Additional paid-in capital	1,339,226	1,357,131
Accumulated other comprehensive income (loss)	(5,239)	(17,311)
Distributions in excess of accumulated earnings	(550,794)	(571,740)
Total stockholders' equity	783,203	768,091
Total liabilities and stockholders' equity	$ 1,364,173	$ 1,793,184

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Consolidated Balance Sheets
Acquired real estate leases, accumulated amortization	$ 40,423	$ 55,447
Office computers and furniture, accumulated depreciation	1,198	1,443
Deferred leasing commissions, accumulated amortization	21,099	30,411
Term loan payable, unamortized financing costs	714	2,677
Series A & Series B Senior notes, unamortized financing costs	658	822
Acquired unfavorable real estate leases, accumulated amortization	$ 2,285	$ 4,031
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	180,000,000	180,000,000
Common stock, shares issued (in shares)	103,998,520	107,328,199
Common stock, shares outstanding (in shares)	103,998,520	107,328,199

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Rental	$ 207,581	$ 244,207	$ 265,527
Total revenues	209,358	245,848	269,065
Expenses:
Real estate operating expenses	60,881	66,940	72,311
Real estate taxes and insurance	41,061	48,390	47,871
Depreciation and amortization	78,544	88,558	90,909
General and administrative	15,898	14,997	14,473
Interest	32,273	36,026	36,757
Total expenses	228,657	254,911	262,321
Loss on extinguishment of debt	(901)
Gain on sale of properties, net	113,134	41,928
Income before taxes and equity in income of non-consolidated REITs	92,934	32,865	6,744
Tax expense	638	250	269
Equity in income of non-consolidated REITs	421
Net Income	$ 92,717	$ 32,615	$ 6,475
Weighted average number of shares outstanding, basic	106,667	107,303	107,233
Weighted average number of shares outstanding, diluted	106,667	107,303	107,233
Net income per share, basic	$ 0.87	$ 0.30	$ 0.06
Net income per share, diluted	$ 0.87	$ 0.30	$ 0.06
Rental
Revenues:
Rental	$ 207,581	$ 244,207	$ 265,527
Related party revenue: Management fees and interest income from loans
Revenues:
Revenue	1,700	1,610	3,517
Related party revenue: Other
Revenues:
Revenue	$ 77	$ 31	$ 21

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Consolidated Statements of Comprehensive Income (Loss)
Net income	$ 92,717	$ 32,615	$ 6,475
Other comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments	12,072	(12,629)	(19,447)
Total other comprehensive income (loss)	12,072	(12,629)	(19,447)
Comprehensive income (loss)	$ 104,789	$ 19,986	$ (12,972)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated other comprehensive income (loss)	Distributions in excess of accumulated earnings	Total
Balance at Dec. 31, 2018	$ 11	$ 1,356,457	$ 14,765	$ (533,599)	$ 837,634
Balance (in shares) at Dec. 31, 2018	107,231,000
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)			(19,447)	6,475	(12,972)
Equity-based compensation		337			337
Equity-based compensation (in shares)	38,000
Distributions				(38,603)	(38,603)
Balance at Dec. 31, 2019	$ 11	1,356,794	(4,682)	(565,727)	786,396
Balance (in shares) at Dec. 31, 2019	107,269,000
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)			(12,629)	32,615	19,986
Equity-based compensation		337			337
Equity-based compensation (in shares)	59,000
Distributions				(38,628)	(38,628)
Balance at Dec. 31, 2020	$ 11	1,357,131	(17,311)	(571,740)	768,091
Balance (in shares) at Dec. 31, 2020	107,328,000
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)			12,072	92,717	104,789
Repurchased shares	$ (1)	(18,243)			$ (18,244)
Repurchased shares (in shares)	(3,396,000)				(3,396,243)
Equity-based compensation		338			$ 338
Equity-based compensation (in shares)	67,000
Distributions				(71,771)	(71,771)
Balance at Dec. 31, 2021	$ 10	$ 1,339,226	$ (5,239)	$ (550,794)	$ 783,203
Balance (in shares) at Dec. 31, 2021	103,999,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 92,717	$ 32,615	$ 6,475
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	81,041	91,581	93,787
Amortization of above and below market leases	(34)	(313)	(402)
Shares issued as compensation	338	337	337
Loss on extinguishment of debt	901
Gain on sale of properties, net	(113,134)	(41,928)
Equity in income of non-consolidated REITs	(421)
Distributions from non-consolidated REITs	421
Decrease in allowance for doubtful accounts and write-off of accounts receivable		(13)	(71)
Changes in operating assets and liabilities:
Tenant rent receivables	5,702	(3,792)	158
Straight-line rents	(3,930)	(1,685)	(8,876)
Lease acquisition costs	(2,353)	(2,123)	(3,999)
Prepaid expenses and other assets	82	(129)	2,313
Accounts payable and accrued expenses	(11,096)	7,785	3,910
Accrued compensation	786	518	357
Tenant security deposits	(2,458)	(669)	3,027
Payment of deferred leasing commissions	(12,200)	(13,735)	(15,101)
Net cash provided by operating activities	36,362	68,449	81,915
Cash flows from investing activities:
Property improvements, fixtures and equipment	(64,833)	(77,919)	(70,746)
Investment in related party mortgage loan receivable	(3,000)		(2,400)
Repayment of related party mortgage loan receivable			52,060
Proceeds received on sales of real estate assets	573,307	88,958
Proceeds received from liquidating trust			1,470
Net cash provided by (used in) investing activities	505,474	11,039	(19,616)
Cash flows from financing activities:
Distributions to stockholders	(38,491)	(38,628)	(38,603)
Stock repurchases	(18,244)
Borrowings under bank note payable	91,500	105,000	45,000
Repayments of bank note payable	(95,000)	(101,500)	(70,000)
Repayment on term loan payable	(445,000)	(50,000)
Deferred financing costs			(83)
Net cash used in financing activities	(505,235)	(85,128)	(63,686)
Net increase (decrease) in cash, cash equivalents and restricted cash	36,601	(5,640)	(1,387)
Cash, cash equivalents and restricted cash, beginning of year	4,150	9,790	11,177
Cash, cash equivalents and restricted cash, end of period	40,751	4,150	9,790
Cash paid for:
Interest	30,141	33,060	34,470
Taxes	454	477	508
Non-cash investing and financing activities:
Accrued dividend	33,280
Accrued costs for purchases of real estate assets	$ 4,715	$ 8,625	$ 11,012

Organization

Organization	12 Months Ended
	Dec. 31, 2021
Organization
Organization	1. Organization ​ Franklin Street Properties Corp. (“FSP Corp.” or the “Company”), holds, directly and indirectly, 100% of the interest in FSP Investments LLC, FSP Property Management LLC, FSP Holdings LLC and FSP Protective TRS Corp. FSP Property Management LLC provides asset management and property management services. The Company also has a non-controlling common stock interest in two corporations organized to operate as real estate investment trusts (“REIT”). Collectively, the two REITs are referred to as the “Sponsored REITs”. ​ As of December 31, 2021, the Company owned and operated a portfolio of real estate consisting of 24 operating properties, two managed Sponsored REITs and held one promissory note secured by a mortgage on real estate owned by a Sponsored REIT. From time-to-time, the Company may acquire real estate or make additional secured loans. The Company may also pursue, on a selective basis, the sale of its properties in order to take advantage of the value creation and demand for its properties, or for geographic or property specific reasons.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Significant Accounting Policies
Significant Accounting Policies	2. Significant Accounting Policies ​ Basis of Presentation ​ The accompanying consolidated financial statements include all of the accounts of the Company and its majority-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. ​ Estimates and Assumptions ​ The Company prepares its financial statements and related notes in conformity with generally accepted accounting principles in the United States of America (“GAAP”). These principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates in the consolidated financial statements include the allowance for doubtful accounts, allowance for credit losses, purchase price allocations, impairment considerations, useful lives of fixed assets and the valuation of derivatives. ​ Investments in non-consolidated REITs ​ As of December 31, 2021, the Company has a non-controlling common stock interest in two Sponsored REITs in which the Company no longer shares in economic benefit or risk. The Company had a non-controlling common stock interest in another Sponsored REIT and a non-controlling preferred stock interest in additional Sponsored REITs, each of which were liquidated during 2019 or 2018. The Company exercised influence over, but did not control these entities and investments were accounted for using the equity method. Under the equity method of accounting, the Company's cost basis was adjusted by its share of the Sponsored REITs' earnings or losses. ​ The equity investments in Sponsored REITS were reviewed for impairment each reporting period. The Company recorded impairment charges when events or circumstances indicated a decline in the fair value below the carrying value of the investment had occurred and such decline was other-than-temporary. ​ Variable Interest Entities (VIEs) ​ We determine whether an entity is a VIE and, if so, whether it should be consolidated by utilizing judgments and estimates that are inherently subjective. The determination of whether an entity in which we hold a direct or indirect variable interest is a VIE is based on several factors, including whether the entity’s total equity investment at risk upon inception is sufficient to finance the entity’s activities without additional subordinated financial support. We make judgments regarding the sufficiency of the equity at risk based first on a qualitative analysis, and then a quantitative analysis, if necessary. We analyze any investments in VIEs to determine if we are the primary beneficiary. In evaluating whether we are the primary beneficiary, we evaluate our direct and indirect economic interests in the entity. Determining which reporting entity, if any, is the primary beneficiary of a VIE is primarily a qualitative approach focused on identifying which reporting entity has both (1) the power to direct the activities of a VIE that most significantly impact such entity’s economic performance and (2) the obligation to absorb losses or the right to receive benefits from such entity that could potentially be significant to such entity. Performance of that analysis requires the exercise of judgment. ​ We consider a variety of factors in identifying the entity that holds the power to direct matters that most significantly impact the VIE’s economic performance including, but not limited to, the ability to direct a proposed sale of the property or merger of the company. In addition, we consider the rights of other investors to participate in those decisions, to replace the manager and to amend the corporate charter. We determine whether we are the primary beneficiary of a VIE at the time we become involved with a variable interest entity and reconsider that conclusion upon a reconsideration event. As of December 31, 2021, our relationship with FSP Monument Circle LLC was considered a VIE for which we are not the primary beneficiary. Our maximum exposure to losses associated with this VIE is limited to the outstanding Sponsored REIT Loan, the related accrued interest receivable and an exit fee receivable, which were in aggregate approximately $24.5 million at December 31, 2021. The accrued interest and exit fee receivables are included in prepaid expenses and other assets in the consolidated balance sheet and are approximately $0.5 million at December 31, 2021. The relationships and investments related to the entity in which we have a variable interest with are summarized in Note ​ 3, Related Party Transactions and Investments in Non-Consolidated Entities. ​ Real Estate and Depreciation ​ Real estate assets are stated at cost less accumulated depreciation. ​ The Company allocates the value of real estate acquired among land, buildings and identified intangible assets or liabilities. Costs related to land, building and improvements are capitalized. Typical capital items include new roofs, site improvements, various exterior building improvements and major interior renovations. Costs incurred in connection with leasing (primarily tenant improvements and leasing commissions) are capitalized and amortized over the lease period. Routine replacements and ordinary maintenance and repairs that do not extend the life of the asset are expensed as incurred. Depreciation is computed using the straight-line method over the assets’ estimated useful lives as follows: ​ ​ ​ ​ ​ ​ ​ Category Years Commercial buildings ​ 39 ​ ​ Building improvements 15 - 39 ​ Fixtures and equipment 3 - 7 ​ ​ The Company reviews its properties to determine if their carrying amounts will be recovered from future operating cash flows if certain indicators of impairment are identified at those properties. These indicators may include declining tenant occupancy, weak or declining tenant profitability, cash flows or liquidity, the Company’s decision to dispose of an asset before the end of its estimated useful life or legislative, economic, or market changes that permanently reduce the value of the Company’s investment. If indicators of impairment are present, the Company evaluates the carrying value of the property by comparing it to its expected future undiscounted cash flow. If the Company determines that impairment has occurred, the affected assets are reduced to their fair value. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Since cash flows are considered on an undiscounted basis in the analysis that the Company conducts to determine whether an asset has been impaired, the Company’s strategy of holding properties over the long term directly decreases the likelihood of recording an impairment loss. If the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized. The Company did not recognize any impairment losses for the years ended December 31, 2021, 2020 or 2019. ​ Acquired Real Estate Leases and Amortization ​ Acquired real estate leases represent costs associated with acquiring an in-place lease (i.e., the market cost to execute a similar lease, including leasing commission, tenant improvements, legal, vacancy and other related costs) and the value relating to leases with rents above the market rate. Amortization is computed using the straight-line method over the term of the leases, which range from 12 months to 154 months . Amortization of these combined components was approximately $8.2 million, $12.5 million and $18.9 million for the years ended December 31, 2021, 2020 and 2019, respectively. ​ Amortization related to costs associated with acquiring an in-place lease is included in depreciation and amortization on the consolidated statements of income. Amortization related to leases with rents above the market rate is offset against the rental revenue in the consolidated statements of income. The estimated annual amortization expense for the five years and thereafter following December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 ​ $ 3,882 ​ 2023 ​ 3,211 ​ 2024 ​ 2,870 ​ 2025 ​ 2,196 ​ 2026 ​ 1,789 ​ 2027 and thereafter ​ 986 ​ ​ Acquired Unfavorable Real Estate Leases and Amortization ​ Acquired unfavorable real estate leases represent the value relating to leases with rents below the market rate. Amortization is computed using the straight-line method over the term of the leases, which range from 64 months to 151 months . Amortization expense was approximately $0.5 million, $0.9 million and $1.3 million for the years ended December 31, 2021, 2020 and 2019, respectively. ​ Amortization related to leases with rents below the market rate is included with rental revenue in the consolidated statements of income. The estimated annual amortization for the five years and thereafter following December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 ​ $ 161 ​ 2023 ​ 104 ​ 2024 ​ 93 ​ 2025 ​ 60 ​ 2026 ​ 31 ​ 2027 and thereafter ​ 79 ​ ​ Asset Held For Sale ​ Classification of a property as held for sale typically occurs upon the execution of a purchase and sale agreement and belief by management that the sale or disposition is probable of occurrence within one year . Upon determining that a property was held for sale, the Company discontinues depreciating the property and reflects the property in its consolidated balance sheet at the lower of its carrying amount or fair value less the cost to sell. The Company presents the property held for sale on its consolidated balance sheet as “Asset held for sale”. The Company reports the results of operations of its properties sold or held for sale in its consolidated statements of income through the date of sale. ​ Cash and Cash Equivalents ​ The Company considers all highly liquid instruments purchased with an original maturity of three months or less to be cash equivalents. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statement of cash flows. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 34,308 ​ $ 2,650 Restricted cash ​ 6,443 ​ 1,500 Total cash, cash equivalents and restricted cash ​ $ 40,751 ​ $ 4,150 ​ ​ Restricted Cash ​ Restricted cash consists of tenant security deposits, which are required by law in some states or by contractual agreement to be kept in a segregated account, and escrows arising from property sales. Tenant security deposits are refunded when tenants vacate, provided that the tenant has not damaged the property. ​ Cash held in escrow is paid when the related issue is resolved. Restricted cash also may include funds segregated for specific tenant improvements per lease agreements. ​ Tenant Rent Receivables ​ Tenant rent receivables are expected to be collected within one year . The Company provided an allowance for doubtful accounts based on collectability. The Company recognizes the effect of a change in its assessment of whether the collectability of operating lease receivables are probable as an adjustment to lease income rather than bad debt expense. ​ Related Party Mortgage Loan Receivable ​ Management monitors and evaluates the secured loans compared to the expected performance, cash flow and value of the underlying real estate and has not experienced a loss on these loans to date. ​ Concentration of Credit Risks ​ Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash investments, derivatives, related party mortgage loan receivable and accounts receivable. The Company maintains its cash balances principally in banks which the Company believes to be creditworthy. The Company periodically assesses the financial condition of the banks and believes that the risk of loss is minimal. Cash balances held with various financial institutions frequently exceed the insurance limit of provided by the Federal Deposit Insurance Corporation. The derivatives that the Company has are from interest rate swap agreements that are discussed in Note 5. The related party mortgage loan receivable is held with Sponsored REIT. The Company performs regular evaluations on the extent and impact of any credit deterioration that could affect the performance and value of the secured property, as well as the financial and operating capability of the borrower. The Company performs ongoing credit evaluations of its tenants and requires certain tenants to provide security deposits or letters of credit. Though these security deposits and letters of credit are insufficient to meet the total value of a tenant’s lease obligation, they are a measure of good faith and a source of funds to offset the economic costs associated with lost rent and the costs associated with re-tenanting the space. The Company has no single tenant which accounts for more than ​ Financial Instruments ​ The Company estimates that the carrying values of cash and cash equivalents, restricted cash, receivables, prepaid expenses, accounts payable and accrued expenses, accrued compensation, and tenant security deposits approximate their fair values based on their short-term maturity and the bank note and term loans payable approximate their fair values as they bear interest at variable interest rates. ​ Straight-line Rent Receivable ​ Certain leases provide for fixed rent increases over the term of the lease. Rental revenue is recognized on a straight-line basis over the related lease term; however, billings by the Company are based on the lease agreements. Straight-line rent receivable, which is the cumulative revenue recognized in excess of amounts billed by the Company, was 31, 2021, 2020 and 2019, respectively. Prior to 2020, the Company provided an allowance for doubtful accounts based on collectability. The Company recognized the effect of a change in its assessment of whether the collectability of operating lease receivables are probable as an adjustment to lease income rather than bad debt expense. The reserve was eliminated during 2020 and no changes occurred during 2019 based on such assessment. ​ Deferred Leasing Commissions ​ Deferred leasing commissions represent direct and incremental external leasing costs incurred in the leasing of commercial space. These costs are capitalized and are amortized on a straight-line basis over the terms of the related lease agreements. Amortization expense was approximately ​ The estimated annual amortization for the five years and thereafter following December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 $ 6,504 ​ 2023 6,081 ​ 2024 5,299 ​ 2025 4,377 ​ 2026 3,586 ​ 2027 and thereafter 12,464 ​ ​ Common Share Repurchases ​ The Company recognizes the gross cost of the common shares it repurchases as a reduction in stockholders’ equity using the treasury stock method. Maryland law does not recognize a separate treasury stock account but provides that shares repurchased are classified as authorized but unissued shares. Accordingly, the Company reduces common stock for the par value and the excess of the purchase price over the par value is a reduction to additional paid-in capital. ​ Revenue Recognition ​ Rental Revenue - The Company has retained substantially all of the risks and benefits of ownership of the Company’s commercial properties and accounts for its leases as operating leases. Rental revenue includes income from leases, certain reimbursable expenses, straight-line rent adjustments and other income associated with renting the property. Rental income from leases, which includes rent concessions (including free rent and other lease inducements) and scheduled increases in rental rates during the lease term, is recognized on a straight-line basis. The Company does not have any significant percentage rent arrangements with its commercial property tenants. Reimbursable expenses are included in rental income in the period earned. A summary of rental revenue is shown in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, (in thousands) 2021 2020 2019 Income from leases ​ $ 148,705 ​ $ 180,899 ​ $ 191,828 ​ Reimbursable expenses ​ 54,825 ​ 61,310 ​ 64,421 ​ Straight-line rent adjustment ​ 4,017 ​ 1,685 ​ 8,876 ​ Amortization of favorable and unfavorable leases ​ 34 ​ 313 ​ 402 ​ ​ ​ $ 207,581 ​ $ 244,207 ​ $ 265,527 ​ ​ Related Party and Other Revenue - ​ Segment Reporting ​ The Company is a REIT focused on real estate investments primarily in the office market and currently operates in only one segment: real estate operations. ​ Income Taxes ​ Taxes on income for the years ended December 31, 2021, 2020 and 2019 represent taxes incurred by FSP Protective TRS Corp, which is a taxable REIT subsidiary, and the State of Texas franchise tax applicable to FSP Corp., which is classified as an income tax for reporting purposes. ​ Net Income Per Share ​ Basic net income per share is computed by dividing net income by the weighted average number of shares outstanding during the period. Diluted net income per share reflects the potential dilution that could occur if securities or other contracts to issue shares were exercised or converted into shares. There were ​ Derivative Instruments ​ The Company recognizes derivatives on the consolidated balance sheets at fair value. Derivatives that do not qualify, or are not designated as hedge relationships, must be adjusted to fair value through income. Derivative instruments designated in a hedge relationship to mitigate exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Cash flow hedges are accounted for by recording the fair value of the derivative instrument on the consolidated balance sheets as either an asset or liability. To the extent hedges are effective, a corresponding amount, adjusted for swap payments, is recorded in accumulated other comprehensive income within stockholders’ equity. Amounts are then reclassified from accumulated other comprehensive income to the income statement in the period or periods the hedged forecasted transaction affects earnings. Ineffectiveness, if any, is recognized in other comprehensive income (“OCI”) and reclassified into the income statement. The Company reviews the effectiveness of each hedging transaction, which involves estimating future cash flows, at least quarterly. Derivative instruments designated in a hedge relationship to mitigate exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. The Company currently has ​ Fair Value Measurements ​ Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. There is also an established fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value. Financial assets and liabilities recorded on the consolidated balance sheets at fair value are categorized based on the inputs to the valuation techniques as follows: ​ Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, which is typically based on an entity’s own assumptions, as there is little, if any, related market activity or information. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability including credit risk, which was not significant to the overall value. These inputs (See Notes 3 and 5) were considered and applied to the Company’s derivative instruments and Sponsored REIT Loan. Level 2 inputs were used to value the interest rate swaps and Level 3 inputs were used to value the Sponsored REIT Loan. ​ Subsequent Events ​ In preparing these consolidated financial statements the Company evaluated events that occurred through the date of issuance of these financial statements for potential recognition or disclosure. ​ Recent Accounting Standards ​ In March 2020, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). ASU 2020-04 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. The Company is currently assessing the potential impact that the adoption of ASU 2020-04 may have on its consolidated financial statements.

Related Party Transactions and

Related Party Transactions and Investments in Non-Consolidated Entities	12 Months Ended
	Dec. 31, 2021
Related Party Transactions and Investments in Non-Consolidated Entities
Related Party Transactions and Investments in Non-Consolidated Entities	3. Related Party Transactions and Investments in Non-Consolidated Entities ​ Investment in Sponsored REITs ​ The Company held a common stock interest in 2 Sponsored REITs at December 31, 2021, 2020 and 2019. The Company held a non-controlling preferred stock investment in Sponsored REITs, FSP 303 East Wacker Drive Corp. (“East Wacker”) and FSP Grand Boulevard Corp. (“Grand Boulevard”), each of which were liquidated during the three months ended September 30, 2018. ​ Equity in income (loss) of investments in non-consolidated REITs were derived from the Company’s share of income or loss in the operations of those entities and includes gain or loss on liquidation. The Company exercised influence over, but did not control these entities, and investments were accounted for using the equity method. ​ During the year ended December 31, 2019, a property owned by a Sponsored REIT, FSP Energy Tower I Corp. (“Energy Tower”), was sold and, thereafter, liquidating distributions for its preferred shareholders were declared and issued. The Company held a mortgage loan and secured revolving line of credit with this entity, which were secured by the property owned by Energy Tower. The loans with Energy Tower in the aggregate principal amount of million were repaid by the proceeds of the sale. ​ Equity in income of investment in non-consolidated REITs: ​ The following table includes equity in income of investments in non-consolidated REITs: ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ ​ ​ December 31, ​ (in thousands) 2021 ​ ​ ​ ​ Equity in income of East Wacker ​ $ 421 ​ Total ​ $ 421 ​ ​ Equity in income of East Wacker was derived from the Company’s preferred stock investment in the entity. In December 2007, the Company purchased of the outstanding preferred shares, of East Wacker. On September 24, 2018, the property owned by East Wacker was sold at a gain. On October 6, 2021, the Company received a liquidating distribution of million, which is included in equity in income of non-consolidated REITs on the consolidated statements of income. ​ The following table includes distributions received from non-consolidated REITs: ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ ​ ​ December 31, ​ (in thousands) 2021 ​ ​ ​ ​ ​ Distributions from East Wacker ​ $ 421 ​ ​ ​ $ 421 ​ ​ Non-consolidated REITs ​ As of December 31, 2021, the Company has a non-controlling common stock interest in two Sponsored REITs in which the Company no longer shares in economic benefit or risk. ​ Management fees and interest income from loans: ​ Asset management fees range from 1% to 5% of collected rents, and the applicable contracts are cancelable with 30 day notice. Asset management fee income from non-consolidated entities amounted to approximately $0.1 million, $0.1 million and $0.2 million for the years ended December 31, 2021, 2020 and 2019, respectively. ​ From time to time the Company may make secured loans (“Sponsored REIT Loans”) to Sponsored REITs in the form of mortgage loans or revolving lines of credit to fund construction costs, capital expenditures, leasing costs and for other purposes. The Company reviews the need for an allowance under CECL for Sponsored REIT loans at each reporting period. The measurement of expected credit losses is based upon historical experiences, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The Company has elected to apply the practical expedient for financial assets secured by collateral in instances where the borrower is experiencing financial difficulty and repayment of the Sponsored REIT Loan is expected to be provided substantially through operation or sale of the collateral. The Company uses the fair value of the collateral at the reporting date and an adjustment to the allowance for expected credit losses is recorded when the amortized cost basis of the financial asset exceeds the fair value of the collateral, less costs to sell. ​ The Company regularly evaluates the extent and impact of any credit deterioration that could affect performance and the value of the secured property, as well as the financial and operating capability of the borrower. A property’s operating results and existing cash balances are considered and used to assess whether cash flows from operations are sufficient to cover the current and future operating and debt service requirements. The Company also evaluates the borrower’s competency in managing and operating the secured property and considers the overall economic environment, real estate sector and geographic sub-market in which the secured property is located. The Company applies normal loan review and underwriting procedures (as may be implemented or modified from time to time) in making that judgment. ​ The Company anticipates that each Sponsored REIT Loan will be repaid at maturity or earlier from refinancing, long term financings of the underlying properties, cash flows from the underlying properties or some other capital event. Each Sponsored REIT Loan is secured by a mortgage on the underlying property and has a term of approximately one to three years . ​ The following is a summary of the Sponsored REIT Loan outstanding as of December 31, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maximum Amount Interest (dollars in thousands, except footnotes) ​ ​ Maturity ​ Amount ​ Outstanding Rate at Sponsored REIT Location ​ Date ​ of Loan ​ 31-Dec-21 31-Dec-21 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mortgage loan secured by property ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ FSP Monument Circle LLC (1) ​ Indianapolis, IN ​ 30-Jun-23 ​ $ 24,000 ​ $ 24,000 7.51 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 24,000 ​ $ 24,000 ​ ​ (1) This mortgage loan includes an origination fee of $164,000 and an exit fee of $38,000 when repaid by the borrower. ​ The Company recognized interest income and fees from the Sponsored REIT Loans of approximately $1.6 million, $1.5 million and $3.3 million for the years ended December 31, 2021, 2020 and 2019, respectively. The financial instrument was classified within Level 3 of the fair value hierarchy and had a fair value of approximately million as of December 31, 2021. ​ On October 29, 2021, the Company agreed to amend and restate its existing Sponsored REIT Loan to FSP Monument Circle LLC to extend the maturity date from December 6, 2022 to June 30, 2023 and to advance an additional $3.0 million tranche of indebtedness to FSP Monument Circle LLC with the same June 30, 2023 maturity date, effectively increasing the aggregate principal amount of the Sponsored REIT Loan from $21 million to $24 million. In addition, the Company agreed to defer all principal and interest payments due under the Sponsored REIT Loan until the maturity date on June 30, 2023. As part of its consideration for agreeing to amend and restate the Sponsored REIT Loan, the Company obtained from the stockholders of the parent of FSP Monument Circle LLC the right to vote their shares in favor of any sale of the property owned by FSP Monument Circle LLC any time on or after January 1, 2023. The amended and restated Sponsored REIT Loan qualified as a troubled debt restructuring. There were ​ On December 6, 2020, the Company entered into a second amendment to the Sponsored REIT Loan which qualified as a troubled debt restructuring. The amendment extended the maturity date of the loan for two years and increased the interest rate from 7.19% to 7.51% .

Bank Note Payable, Term Note Pa

Bank Note Payable, Term Note Payable and Private Placements	12 Months Ended
	Dec. 31, 2021
Bank Note Payable, Term Note Payable and Private Placements
Bank Note Payable, Term Note Payable and Senior Notes	4. Bank Note Payable, Term Note Payable and Private Placements ​ JPM Term Loan ​ On August 2, 2018, the Company entered into an Amended and Restated Credit Agreement with JPMorgan Chase Bank, N.A., as administrative agent and lender (“JPMorgan”), and the other lending institutions party thereto (the “JPM Credit Agreement”), which provides a single unsecured bridge loan in the aggregate principal amount of $150 million (the “JPM Term Loan”). On December 24, 2020 the Company repaid a million remained fully advanced and outstanding under the JPM Term Loan. On June 4, 2021, the Company repaid the remaining million related to unamortized deferred financing costs. ​ Although the interest rate on the JPM Term Loan was variable under the JPM Credit Agreement, the Company fixed the LIBOR-based rate on a portion of the JPM Term Loan by entering into interest rate swap transactions. On March 7, 2019, the Company entered into ISDA Master Agreements with various financial institutions to hedge a $100 million portion of the future LIBOR-based rate risk under the JPM Credit Agreement. Effective March 29, 2019, the Company fixed the LIBOR-based rate at million portion of the JPM Term Loan until November 30, 2021. On June 4, 2021, the Company paid approximately million to terminate the interest rate swap, which was scheduled to mature on November 30, 2021. ​ BMO Term Loan ​ On September 27, 2018, the Company entered into a Second Amended and Restated Credit Agreement with the lending institutions party thereto and Bank of Montreal (“BMO”), as administrative agent (the “BMO Credit Agreement”). The BMO Credit Agreement provides for a single, unsecured term loan borrowing in the initial amount of $220 million (the “BMO Term Loan”), of which $165 million remains fully advanced and outstanding. The BMO Term Loan initially consisted of a $55 million tranche A term loan and a $165 million tranche B term loan. On June 4, 2021, the Company repaid the tranche A term loan that was scheduled to mature on November 30, 2021, and incurred a loss on extinguishment of debt of million related to unamortized deferred financing costs. The million tranche B term loan matures on January 31, 2024. The BMO Credit Agreement also includes an accordion feature that allows up to million of additional loans, subject to receipt of lender commitments and satisfaction of certain customary conditions. The BMO Term Loan was previously evidenced by an Amended and Restated Credit Agreement, dated October 29, 2014, among the Company, BMO, as administrative agent and lender, and the other lending institutions party thereto, as amended by a First Amendment, dated July 21, 2016, and a Second Amendment, dated October 18, 2017. ​ The BMO Term Loan bears interest at either (i) a number of basis points over LIBOR depending on the Company’s credit rating (165 basis points over LIBOR at December 31, 2021) or (ii) a number of basis points over the base rate depending on the Company’s credit rating (65 basis points over the base rate at December 31, 2021). The margin over LIBOR rate or base rate is determined based on the Company’s credit rating pursuant to the following grid: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit ​ LIBOR Rate ​ Base Rate ​ Level Rating Margin Margin I ​ A- / A3 (or higher) ​ 85.0 bps — bps II ​ BBB+ / Baa1 ​ ​ 90.0 bps — bps III ​ BBB / Baa2 ​ ​ 100.0 bps — bps IV ​ BBB- / Baa3 ​ ​ 125.0 bps 25.0 bps V ​ <BBB- / Baa3 ​ ​ 165.0 bps 65.0 bps ​ For purposes of the BMO Term Loan, base rate means, for any day, a fluctuating rate per annum equal to the highest of: (i) the bank’s prime rate for such day, (ii) the Federal Funds Rate for such day, plus 0.50%, and (iii) the one month LIBOR based rate for such day plus 1.00%. As of December 31, 2021, the Company’s credit rating from Moody’s Investors Service was Ba1. ​ Although the interest rate on the BMO Term Loan is variable under the BMO Credit Agreement, the Company fixed the base LIBOR interest rate by entering into interest rate swap transactions. On August 26, 2013, the Company entered into an ISDA Master Agreement with Bank of Montreal that fixed the base LIBOR interest rate on the BMO Term Loan at 2.32% per annum, which matured on August 26, 2020. On February 20, 2019, the Company entered into ISDA Master Agreements with a group of banks that fixed the base LIBOR interest rate on the BMO Term Loan at per annum for the period beginning on August 26, 2020 and ending January 31, 2024. Accordingly, based upon the Company’s credit rating, as of December 31, 2021, the effective interest rate on the BMO Term Loan was per annum. On June 4, 2021, the Company paid approximately million to terminate the portion of the interest rate swap on the tranche A term loan, which was scheduled to mature on November 30, 2021. ​ The BMO Credit Agreement contains customary affirmative and negative covenants for credit facilities of this type, including limitations with respect to indebtedness, liens, investments, mergers and acquisitions, disposition of assets, changes in business, certain restricted payments, the requirement to have subsidiaries provide a guaranty in the event that they incur recourse indebtedness and transactions with affiliates. The BMO Credit Agreement also contains financial covenants that require the Company to maintain a minimum tangible net worth, a maximum leverage ratio, a maximum secured leverage ratio, a minimum fixed charge coverage ratio, a maximum unencumbered leverage ratio, and minimum unsecured interest coverage. The BMO Credit Agreement provides for customary events of default with corresponding grace periods, including failure to pay any principal or interest when due, certain cross defaults and a change in control of the Company (as defined in the BMO Credit Agreement). In the event of a default by the Company, the administrative agent may, and at the request of the requisite number of lenders shall, declare all obligations under the BMO Credit Agreement immediately due and payable, terminate the lenders’ commitments to make loans under the BMO Credit Agreement, and enforce any and all rights of the lenders or administrative agent under the BMO Credit Agreement and related documents. For certain events of default related to bankruptcy, insolvency, and receivership, the commitments of lenders will be automatically terminated and all outstanding obligations of the Company will become immediately due and payable. The Company was in compliance with the BMO Term Loan financial covenants as of December 31, 2021. ​ BofA Credit Facility ​ On July 21, 2016, the Company entered into a First Amendment (the “BofA First Amendment”), and on October 18, 2017, the Company entered into a Second Amendment (the “BofA Second Amendment”), to the Second Amended and Restated Credit Agreement dated October 29, 2014 among the Company, the lending institutions party thereto and BofA, as administrative agent, L/C Issuer and Swing Line Lender (as amended by the BofA First Amendment and the BofA Second Amendment, the “BofA Credit Facility”) that continued an existing unsecured revolving line of credit (the “Former BofA Revolver”) and an existing term loan (the “BofA Term Loan”). Effective simultaneously with the closing of the BofA Revolver (as defined in Note 11 to these Consolidated Financial Statements) on January 10, 2022, the Company delivered a notice to BofA terminating the aggregate lender commitments under the Former BofA Revolver in their entirety. ​ Former BofA Revolver Highlights ​ ● As of December 31, 2021, there were no borrowings under the Former BofA Revolver. ● The Former BofA Revolver was for borrowings, at the Company's election, of up to $600 million. Borrowings made pursuant to the Former BofA Revolver could be revolving loans, swing line loans or letters of credit, the combined sum of which could not exceed $600 million outstanding at any time. ​ As of December 31, 2021, there were no borrowings outstanding under the Former BofA Revolver. The Former BofA Revolver bore interest at either (i) a margin over LIBOR depending on the Company’s credit rating ( ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Base ​ ​ ​ ​ ​ LIBOR Rate ​ Facility ​ Rate ​ Level Credit Rating Margin Fee Margin I A- / A3 (or higher) 0.825 % 0.125 % 0.000 % II BBB+ / Baa1 ​ 0.875 % 0.150 % 0.000 % III BBB / Baa2 ​ 1.000 % 0.200 % 0.000 % IV BBB- / Baa3 ​ 1.200 % 0.250 % 0.200 % V <BBB- / Baa3 ​ 1.550 % 0.300 % 0.550 % ​ For purposes of the BofA Credit Facility, base rate means, for any day, a fluctuating rate per annum equal to the highest of: (i) the bank’s prime rate for such day, (ii) the Federal Funds Rate for such day, plus 0.50%, and (iii) the one month LIBOR based rate for such day plus 1.00%. As of December 31, 2021, the Company’s credit rating from Moody’s Investors Service was Ba1. ​ Based upon the Company’s credit rating, as of December 31, 2021, the interest rate on the Former BofA Revolver would have been 1.65% per annum. The weighted average interest rate on all amounts outstanding on the Former BofA Revolver during the year ended December 31, 2021, was approximately per annum. As of December 31, 2020, there were borrowings of million outstanding under the Former BofA Revolver. The weighted average interest rate on all amounts outstanding on the Former BofA Revolver during the year ended December 31, 2020, was approximately per annum. ​ BofA Term Loan Highlights ​ ● The original principal amount of the BofA Term Loan was $400 million. On September 30, 2021, the Company repaid a $90 million portion and on October 25, 2021, the Company repaid a $200 million portion of the BofA Term Loan and incurred a loss on extinguishment of debt of $0.7 million related to unamortized deferred financing costs. As of December 31, 2021, $110 million remained outstanding under the BofA Term Loan. ● The BofA Term Loan matures on January 12, 2023. ● The BofA Credit Facility includes an accordion feature that allows for an aggregate amount of up to $500 million of additional borrowing capacity to the Former BofA Revolver and/or the BofA Term Loan, subject to receipt of lender commitments and satisfaction of certain customary condition s. ​ The BofA Term Loan bears interest at either (i) a margin over LIBOR depending on the Company’s credit rating (1.75% over LIBOR at December 31, 2021) or (ii) a margin over the base rate depending on the Company’s credit rating (0.750% over the base rate at December 31, 2021). The margin over LIBOR rate or base rate is determined based on the Company’s credit rating pursuant to the following grid: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ LIBOR Rate ​ Base Rate ​ Level Credit Rating Margin Margin I A- / A3 (or higher) 0.900 % 0.000 % II BBB+ / Baa1 ​ 0.950 % 0.000 % III BBB / Baa2 ​ 1.100 % 0.100 % IV BBB- / Baa3 ​ 1.350 % 0.350 % V <BBB- / Baa3 ​ 1.750 % 0.750 % ​ For purposes of the BofA Credit Facility, base rate means, for any day, a fluctuating rate per annum equal to the highest of: (i) the bank’s prime rate for such day, (ii) the Federal Funds Rate for such day, plus 0.50%, and (iii) the one month LIBOR based rate for such day plus 1.00%. As of December 31, 2021, the Company’s credit rating from Moody’s Investors Service was Ba1. ​ The interest rate on the BofA Term Loan was variable at December 31, 2021. Previously the Company had fixed the base LIBOR interest rate on the BofA Term Loan by entering into interest rate swap transactions. On July 22, 2016, the Company entered into ISDA Master Agreements with a group of banks that fixed the base LIBOR interest rate on the BofA Term Loan at per annum for the period beginning on September 27, 2017 and ended on September 27, 2021. Based upon the Company’s credit rating, as of December 31, 2021, the interest rate on the BofA Term Loan was per annum. The weighted average variable interest rate on all amounts outstanding under the BofA Term Loan after the expiration of the interest rate swaps, on September 27, 2021, during the period from September 28 through December 31, 2021, was approximately per annum. ​ BofA Credit Facility General Information ​ The BofA Credit Facility contains customary affirmative and negative covenants for credit facilities of this type, including limitations with respect to indebtedness, liens, investments, mergers and acquisitions, disposition of assets, changes in business, certain restricted payments, the requirement to have subsidiaries provide a guaranty in the event that they incur recourse indebtedness and transactions with affiliates. The BofA Credit Facility also contains financial covenants that require the Company to maintain a minimum tangible net worth, a maximum leverage ratio, a maximum secured leverage ratio, a minimum fixed charge coverage ratio, a maximum unencumbered leverage ratio, and minimum unsecured interest coverage. The BofA Credit Facility provides for customary events of default with corresponding grace periods, including failure to pay any principal or interest when due, certain cross defaults and a change in control of the Company (as defined in the BofA Credit Facility). In the event of a default by the Company, the administrative agent may, and at the request of the requisite number of lenders shall, declare all obligations under the BofA Credit Facility immediately due and payable, terminate the lenders’ commitments to make loans under the BofA Credit Facility, and enforce any and all rights of the lenders or administrative agent under the BofA Credit Facility and related documents. For certain events of default related to bankruptcy, insolvency, and receivership, the commitments of lenders will be automatically terminated and all outstanding obligations of the Company will become immediately due and payable. We were in compliance with the BofA Credit Facility financial covenants as of December 31, 2021. ​ The Company may use the proceeds of the loans under the BofA Credit Facility to finance the acquisition of real properties and for other permitted investments; to finance investments associated with Sponsored REITs, to refinance or retire indebtedness and for working capital and other general business purposes, in each case to the extent permitted under the BofA Credit Facility. ​ Senior Notes ​ On October 24, 2017, the Company entered into a note purchase agreement (the “Note Purchase Agreement”) with the various purchasers named therein (the “Purchasers”) in connection with a private placement of senior unsecured notes. Under the Note Purchase Agreement, the Company agreed to sell to the Purchasers an aggregate principal amount of $200,000,000 of senior unsecured notes consisting of (i) Series A Senior Notes due December 20, 2024 in an aggregate principal amount of $116 million (the “Series A Notes”) and (ii) Series B Senior Notes due December 20, 2027 in an aggregate principal amount of $84 million (the “Series B Notes,” and, together with the Series A Notes, the “Senior Notes”). On December 20, 2017, the Senior Notes were funded and the proceeds were used to reduce the outstanding balance of the Former BofA Revolver. ​ The Senior Notes bear interest depending on the Company’s credit rating. As of December 31, 2021, the Series A Notes bear interest at 4.49% per annum and the Series B Notes bear interest at 4.76% per annum. ​ The Note Purchase Agreement contains customary financial covenants, including a maximum leverage ratio, a maximum secured leverage ratio, a minimum fixed charge coverage ratio, and a maximum unencumbered leverage ratio. The Note Purchase Agreement also contains restrictive covenants that, among other things, restrict the ability of the Company and its subsidiaries to enter into transactions with affiliates, merge, consolidate, create liens, make certain restricted payments, enter into certain agreements or prepay certain indebtedness. Such financial and restrictive covenants are substantially similar to the corresponding covenants contained in the BofA Credit Facility, the BMO Credit Agreement and the JPM Credit Agreement. The Senior Notes financial covenants require, among other things, the maintenance of a fixed charge coverage ratio of at least 1.50; a maximum leverage ratio and an unsecured leverage ratio of no more than 60% (65% if there were a significant acquisition for a short period of time). In addition, the Note Purchase Agreement provides that the Note Purchase Agreement will automatically incorporate additional financial and other specified covenants (such as limitations on investments and distributions) that are effective from time to time under the existing credit agreements, other material indebtedness or certain other private placements of debt of the Company and its subsidiaries. The Note Purchase Agreement contains customary events of default, including payment defaults, cross defaults with certain other indebtedness, breaches of covenants and bankruptcy events. In the case of an event of default, the Purchasers may, among other remedies, accelerate the payment of all obligations. The Company was in compliance with the Senior Notes financial covenants as of December 31, 2021.

Financial Instruments_ Derivati

Financial Instruments: Derivatives and Hedging	12 Months Ended
	Dec. 31, 2021
Financial Instruments: Derivatives and Hedging
Financial Instruments: Derivatives and Hedging	5. Financial Instruments: Derivatives and Hedging ​ On July 22, 2016, the Company fixed the interest rate for the period beginning on September 27, 2017 and ending on September 27, 2021 on the BofA Term Loan (the “2017 Interest Rate Swap”). On March 7, 2019, the Company fixed the interest rate for the period beginning on March 29, 2019 and ended on November 30, 2021 on a million portion of the JPM Term Loan (the “2019 JPM Interest Rate Swap”). On February 20, 2019, the Company fixed the interest rate for the period beginning August 26, 2020 and ending January 31, 2024 on the BMO Term Loan (the “2019 BMO Interest Rate Swap”). The variable rates that were fixed under the 2017 Interest Rate Swap, the 2019 JPM Interest Rate Swap and the 2019 BMO Interest Rate Swap (collectively referred to as the “Interest Rate Swaps”) are described in Note 4. ​ On June 4, 2021, the Company paid approximately $1.2 million to terminate the 2019 JPM Interest Rate Swap that was scheduled to mature on November 30, 2021 and approximately $0.6 million to terminate a portion of the 2019 BMO Interest Rate Swap that was scheduled to mature on November 30, 2021. As a result of the terminations, approximately million of the balance held in accumulated other comprehensive income (loss) was reclassified into earnings. The JPM Term Loan and a portion of the BMO Term Loan related to these interest rate swaps was also repaid on June 4, 2021, which is described in Note 4. ​ The Interest Rate Swaps qualify as cash flow hedges and have been recognized on the consolidated balance sheets at fair value. If a derivative qualifies as a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will either be offset against the change in fair value of the hedged asset, liability, or firm commitment through earnings, or recognized in other comprehensive income until the hedged item is recognized in earnings. The ineffective portion of a derivative’s change in fair value will be recognized in earnings in the same period in which the hedged interest payments affect earnings, which may increase or decrease reported net income and stockholders’ equity prospectively, depending on future levels of interest rates and other variables affecting the fair values of derivative instruments and hedged items, but will have no effect on cash flows. ​ The following table summarizes the notional and fair value of our derivative financial instruments at December 31, 2021. The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Notional Strike Effective Expiration Fair Value (2) at (in thousands) ​ Value ​ Rate ​ Date ​ Date ​ December 31, 2021 December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2017 Interest Rate Swap ​ $ 400,000 1.12 % Sep-17 Sep-21 ​ $ — ​ $ (2,947) ​ 2019 JPM Interest Rate Swap ​ $ 100,000 2.44 % Mar-19 Nov-21 ​ $ — ​ $ (2,102) ​ 2019 BMO Interest Rate Swap (1) ​ $ 165,000 2.39 % Aug-20 Jan-24 ​ $ (5,239) ​ $ (12,262) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The Notional Value decreased to $165 million on June 4, 2021. ​ (2) Classified within Level 2 of the fair value hierarchy. ​ ​ On December 31, 2021, 2019 BMO Interest Rate Swap was reported as a liability with a fair value of approximately $5.2 million and are included in other liabilities: derivative liabilities in the consolidated balance sheet at December 31, 2021. ​ The gain/(loss) on the Company’s Interest Rate Swaps that was recorded in OCI and the accompanying consolidated statements of income as a component of interest expense for the years ended December 31, 2021, 2020 and 2019, respectively, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ Year Ended December 31, Interest Rate Swaps in Cash Flow Hedging Relationships: 2021 2020 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts of gain (loss) recognized in OCI ​ $ 3,786 ​ $ (20,380) ​ $ (15,119) Amounts of previously recorded gain/(loss) reclassified from OCI into Interest Expense ​ $ (8,286) ​ $ (7,751) ​ $ 4,328 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total amount of Interest Expense presented in the consolidated statements of operations ​ $ 32,273 ​ $ 36,026 ​ $ 36,757 ​ Over time, the unrealized gains and losses held in accumulated other comprehensive income will be reclassified into earnings as an increase or reduction to interest expense in the same periods in which the hedged interest payments affect earnings. The Company estimates that approximately ​ The Company is hedging the exposure to variability in anticipated future interest payments on existing debt. ​ The BMO Term Loan, BofA Term Loan and JPM Term Loan hedging transactions used derivative instruments that involve certain additional risks such as counterparty credit risk, the enforceability of hedging contracts and the risk that unanticipated and significant changes in interest rates will cause a significant loss of basis in either or both of the contracts. The Company requires its derivatives contracts to be with counterparties that have investment grade ratings. As a result, the Company does not anticipate that any counterparty will fail to meet its obligations. However, there can be no assurance that the Company will be able to adequately protect against the foregoing risks or that it will ultimately realize an economic benefit that exceeds the related amounts incurred in connection with engaging in such hedging strategies. ​ The fair value of the Company’s derivative instruments are determined using the net discounted cash flows of the expected cash flows of the derivative based on the market based interest rate curve and are adjusted to reflect credit or nonperformance risk. The risk is estimated by the Company using credit spreads and risk premiums that are observable in the market. These financial instruments were classified within Level 2 of the fair value hierarchy and were classified as an asset or liability on the consolidated balance sheets. ​ The Company’s derivatives are recorded at fair value in other assets: derivative asset and other liabilities: derivative liability in the consolidated balance sheets and the effective portion of the derivatives’ fair value is recorded to other comprehensive income in the consolidated statements of other comprehensive income (loss). ​

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity
Stockholders' Equity	6. Stockholders’ Equity ​ Equity-Based Compensation ​ On May 20, 2002, the stockholders of the Company approved the 2002 Stock Incentive Plan (the “Plan”). The Plan is an equity-based incentive compensation plan, and provides for the grants of up to a maximum of 2,000,000 shares of the Company’s common stock (“Awards”). All of the Company’s employees, officers, directors, consultants and advisors are eligible to be granted Awards. Awards under the Plan are made at the discretion of the Company’s Board of Directors, and have no vesting requirements. Upon granting an Award, the Company will recognize compensation cost equal to the fair value of the Company’s common stock, as determined by the Company’s Board of Directors, on the date of the grant. ​ On December 10, 2019, June 4, 2020 and May 20, 2021, the Company granted shares under the Plan to non-employee directors at a compensation cost of approximately $337,000 at each grant date, which is included in general and administrative expenses in the consolidated statements of income. Such shares were fully vested on the date of issuance and are included in the table below. ​ ​ ​ ​ ​ ​ ​ ​ ​ Shares Available ​ Compensation ​ ​ for Grant ​ Cost ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 ​ ​ 1,944,428 ​ $ — Shares granted 2019 ​ ​ (38,046) ​ ​ 337,500 Balance December 31, 2019 ​ ​ 1,906,382 ​ $ 337,500 Shares granted 2020 ​ ​ (58,998) ​ ​ 337,500 Balance December 31, 2020 ​ ​ 1,847,384 ​ $ 675,000 Shares granted 2021 ​ ​ (66,564) ​ ​ 337,500 Balance December 31, 2021 ​ ​ 1,780,820 ​ $ 1,012,500 ​ ​ ​ ​ ​ ​ ​ ​ Repurchase of Common Stock ​ On June 23, 2021, the Board of Directors of the Company authorized the repurchase of up to $50 million of the Company’s common stock from time to time in the open market, privately negotiated transactions or other manners as permitted by federal securities laws. The repurchase authorization may be suspended or discontinued at any time. The Company subsequently repurchased 3,396,243 shares of common stock during the third and fourth quarter of 2021 at an aggregate cost of approximately $18.2 million at an average cost of approximately $5.37 per share, inclusive of brokerage commissions. The excess of the purchase price over the par value of the shares repurchased is applied to reduce additional paid-in capital. The Company did not effect any repurchases during 2020. ​ A summary of the repurchase of common stock by the Company is shown in the following table: ​ ​ ​ ​ ​ ​ ​ ​ (Cost in thousands) ​ ​ Shares Repurchased ​ Cost Balance December 31, 2020 ​ 1,017,498 $ 18,775 Repurchase of shares ​ ​ 3,396,243 ​ ​ 18,244 Balance, December 31, 2021 ​ ​ 4,413,741 ​ $ 37,019 ​

Federal Income Tax Reporting

Federal Income Tax Reporting	12 Months Ended
	Dec. 31, 2021
Federal Income Tax Reporting
Income Taxes	7. Federal Income Tax Reporting ​ General ​ The Company has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”). As a REIT, the Company generally is entitled to a tax deduction for distributions paid to its shareholders, thereby effectively subjecting the distributed net income of the Company to taxation at the shareholder level only. The Company must comply with a variety of restrictions to maintain its status as a REIT. These restrictions include the type of income it can earn, the type of assets it can hold, the number of shareholders it can have and the concentration of their ownership, and the amount of the Company’s taxable income that must be distributed annually. ​ One such restriction is that the Company generally cannot own more than 10% of the voting power or value of the securities of any one issuer unless the issuer is itself a REIT or a taxable REIT subsidiary (“TRS”). In the case of TRSs, the Company’s ownership of securities in all TRSs generally cannot exceed of the value of all of the Company’s assets. FSP Investments LLC and FSP Protective TRS Corp. are the Company’s taxable REIT subsidiaries operating as taxable corporations under the Code. The TRSs have gross amounts of net operating losses (“NOLs”) available to those taxable corporations of million and million as of each of December 31, 2021 and 2020, respectively. The NOLs created prior to 2018 will expire between 2030 and 2047 and the NOLs generated after 2017 will not expire. A valuation allowance is provided for the full amount of the NOLs as the realization of any tax benefits from such NOLs is not assured. ​ Income taxes are recorded based on the future tax effects of the difference between the tax and financial reporting bases of the Company’s assets and liabilities. In estimating future tax consequences, potential future events are considered except for potential changes in income tax law or in rates. ​ The Company adopted an accounting pronouncement related to uncertainty in income taxes effective January 1, 2007, which did not result in recording a liability, nor was any accrued interest and penalties recognized with the adoption. Accrued interest and penalties will be recorded as income tax expense if the Company records a liability in the future. The Company’s effective tax rate was not affected by the adoption. The Company and one or more of its subsidiaries files income tax returns in the U.S. federal jurisdiction and various state jurisdictions. The statute of limitations for the Company’s income tax returns is generally three years and as such, the Company’s returns that remain subject to examination would be primarily from 2018 and thereafter. ​ The Company is subject to a business tax known as the Revised Texas Franchise Tax. Some of the Company’s leases allow reimbursement by tenants for these amounts because the Revised Texas Franchise Tax replaces a portion of the property tax for school districts. Because the tax base on the Revised Texas Franchise Tax is derived from an income based measure, it is considered an income tax. The Company recorded a provision for the Revised Texas Franchise Tax of million for the years ended December 31, 2021, 2020 and 2019, respectively. ​ Net operating losses ​ Section 382 of the Code restricts a corporation’s ability to use net operating losses (“NOLs”) to offset future taxable income following certain “ownership changes.” Such ownership changes occurred with past mergers and accordingly a portion of the NOLs incurred by the Sponsored REITs available for use by the Company in any particular future taxable year will be limited. To the extent that the Company does not utilize the full amount of the annual NOLs limit, the unused amount may be carried forward to offset taxable income in future years. NOLs expire 20 years after the year in which they arise, and the last of the Company’s NOLs will expire in 2027. Approximately $0.1 million of NOLs expired in 2021. The Company is expecting to use approximately $11.8 million of NOLs in 2021 to offset federal net taxable capital gains resulting from the sale of properties in 2021, therefore approximately $11.8 million of valuation allowances were reversed in 2021. A valuation allowance is provided for the full amount of the gross NOLs available as the realization of any tax benefits remaining from such NOLs is not assured. The gross amount of NOLs available to the Company was approximately $1.1 million and $13.0 million as of each of December 31, 2021 and 2020, respectively with full valuation allowances. ​ Income Tax Expense ​ The income tax expense reflected in the consolidated statements of income relates primiarly to state income taxes as a result of some states that limit the use of net operating losses, which are in Other Taxes, and to a lesser extent, the Revised Texas Franchise Tax. FSP Protective TRS Corp. provides taxable services to tenants at some of the Company’s properties. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, (Dollars in thousands) 2021 2020 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revised Texas Franchise Tax ​ $ 234 ​ $ 250 ​ $ 394 ​ Other Taxes ​ 404 ​ — ​ (125) ​ Tax expense ​ $ 638 ​ $ 250 ​ $ 269 ​ ​ Taxes on income are a current tax expense. No deferred income taxes were provided as there were no material temporary differences between the financial reporting basis and the tax basis of the TRSs. ​ At December 31, 2021, the Company’s net tax basis of its real estate assets is more than the amount set forth in the Company’s consolidated balance sheets by $153.7 million and at December 31, 2020, the Company’s net tax basis of its real estate assets is more than the amount set forth in the Company’s consolidated balance sheets by $253.0 million. ​ Tax Components ​ The following summarizes the tax components of the Company’s common distributions paid per share for the years ended December 31, 2021, 2020 and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ Per Share % Per Share % Per Share % Ordinary income (1) ​ $ — — % $ 0.28 77.51 % $ 0.25 69.96 % Capital gain ​ 0.68 100 % 0.06 16.72 % — — % Return of capital ​ — — % 0.02 5.77 % 0.11 30.04 % Total ​ $ 0.68 100 % $ 0.36 100 % $ 0.36 100 % ​ (1) The 2019 Ordinary income amount includes a qualified distribution, which is a subset of, and included in, the ordinary income amount and is $0.009 per share or 2.52% of total distributions.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases
Leases	8. Leases ​ Leases as a Lessee: ​ The Company entered into a noncancelable contract with a third party to obtain office space that commenced on September 1, 2010. The contract was amended on October 25, 2016 to extend the contract through September 30, 2024. As of December 31, 2021, the Company’s right-of-use asset was $1.1 million, which is included in prepaid and other assets on the consolidated balance sheet as of December 31, 2021. ​ The Company has an option to extend the terms of its office space lease with one 5-year extension option. As of December 31, 2021, the exercise of the extension option was not reasonably certain. Therefore, the extension option is not recognized as part of the Company’s right-of-use asset and lease liability. ​ A discount rate equal to the Company’s incremental borrowing rate was applied to the future monthly contractual lease payments remaining as of December 31, 2021 to compute the lease liability. The incremental borrowing rate is the rate equal to the closest borrowing under the Former BofA Revolver at the time of the Company’s adoption of ASU 2016-02. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Lease Costs ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended (in thousands) ​ December 31, 2021 ​ December 31, 2020 ​ December 31, 2019 Operating lease cost $ 419 ​ $ 419 ​ $ 419 ​ $ 419 ​ $ 419 ​ $ 419 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities ​ 429 ​ ​ 421 ​ ​ 412 Weighted average remaining lease terms in years - operating leases ​ 2.75 ​ ​ 3.75 ​ ​ 4.75 Weighted average discount rate - operating leases ​ 3.86% ​ ​ 3.86% ​ ​ 3.86% ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturity analysis for liabilities Total ​ ​ ​ ​ ​ Undiscounted ​ ​ ​ ​ ​ ​ (in thousands) Cash Flows ​ ​ ​ ​ ​ ​ Discount rate at commencement ​ 3.86% ​ ​ ​ ​ ​ ​ 2022 ​ 438 ​ ​ ​ ​ ​ ​ 2023 ​ 447 ​ ​ ​ ​ ​ ​ 2024 ​ 340 ​ ​ ​ ​ ​ ​ ​ $ 1,225 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Present value lease liability $ 1,159 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Difference between undiscounted cash flows and discounted cash flows $ 66 ​ ​ ​ ​ ​ ​ ​ Leases as a Lessor: ​ The Company is a lessor of commercial real estate with operations that include the leasing of office and industrial properties. Many of the leases with customers contain options to extend leases at a fair market rate and may also include options to terminate leases. The Company considers several inputs when evaluating the amount it expects to derive from its leased assets at the end of the lease terms, such as the remaining useful life, expected market conditions, fair value of lease payments, expected fair values of underlying assets, and expected deployment of the underlying assets. The Company’s strategy to address its risk for the residual value in its commercial real estate is to re-lease the commercial space. ​ The Company has elected to apply the practical expedient to not separate non-lease components from the related lease component of real estate leases. This combined component is primarily comprised of fixed lease payments, early termination fees, common area maintenance cost reimbursements, and parking lease payments. The Company applies ASC 842-Leases to the combined lease and non-lease components. ​ A minority of the Company’s leases are subject to annual changes in the Consumer Price Index (“CPI”). Although increases in the CPI are not estimated as part of the Company’s measurement of straight-line rent revenue, to the extent that the actual CPI is greater or less than the CPI at lease commencement, there could be changes to realized income or loss. ​ For the year ended December 31, 2021, 2020 and 2019, the Company recognized the following amounts of income relating to lease payments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income relating to lease payments: ​ ​ ​ ​ Year Ended (in thousands) December 31, 2021 ​ December 31, 2020 December 31, 2019 Income from leases (1) ​ $ 203,530 ​ $ 242,209 ​ $ 256,250 ​ ​ $ 203,530 ​ $ 242,209 ​ $ 256,250 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Undiscounted Cash Flows Year ending ​ ​ ​ ​ ​ ​ (in thousands) ​ December 31, ​ ​ ​ ​ ​ ​ 2022 ​ ​ 100,269 ​ ​ ​ ​ ​ ​ 2023 ​ ​ 103,107 ​ ​ ​ ​ ​ ​ 2024 ​ ​ 97,792 ​ ​ ​ ​ ​ ​ 2025 ​ ​ 83,596 ​ ​ ​ ​ ​ ​ 2026 ​ ​ 70,718 ​ ​ ​ ​ ​ ​ 2027 and thereafter ​ 259,673 ​ ​ ​ ​ ​ ​ ​ ​ $ 715,155 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Amounts recognized from variable lease payments were $54,825, $61,310 and $64,421 for the years ended December 31, 2021, 2020 and 2019, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2021
Retirement Plan
Retirement Plan	9. Retirement Plan ​ In 2006, the Company established a 401(k) plan to cover eligible employees, which permitted deferral of up to $17,000 per year (indexed for inflation) into the 401(k) plan, subject to certain limitations imposed by the Internal Revenue Code. An employee’s elective deferrals are immediately vested upon contribution to the 401(k) plan. The Company matches employee contributions to the 401(k) plan dollar for dollar up to 3% of each employee’s annual compensation up to $200,000. In addition, we may elect to make an annual discretionary profit-sharing contribution. The Company’s total contribution under the 401(k) plan amounted to $0.1 million, $0.1 million and $0.2 million for the years ended December 31, 2021, 2020 and 2019, respectively.

Dispositions of Property

Dispositions of Property	12 Months Ended
	Dec. 31, 2021
Dispositions of property
Dispositions of properties	10. Dispositions of Property ​ In 2021, the Company determined that further debt reduction would provide greater financial flexibility and potentially increase shareholder value. Accordingly, the Company adopted a strategy to dispose of certain properties in 2021 where it believes valuation potential has been reached. The Company sold million. The Company sold an office property in Dulles, Virginia on June 29, 2021 for a sales price of approximately million. The Company sold an office property located in Indianapolis, Indiana on August 31, 2021 for a sales price of approximately million. The Company sold million. The Company sold an office property in Atlanta, Georgia on October 22, 2021, for a sales price of approximately million. The Company sold million. The Company used the proceeds of the dispositions principally to repay outstanding indebtedness. ​ The Company sold an office property located in Durham, North Carolina on December 23, 2020 for a sales price of approximately $89.7 million, at a gain of approximately $41.9 million. ​ The Company reports the results of operations of its properties in its consolidated statements of operations, which includes rental income, rental operating expenses, real estate taxes and insurance and depreciation and amortization. ​ The operating results for the properties that the Company disposed of are summarized below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended ​ ​ December 31, (in thousands) 2021 2020 ​ 2019 Rental revenue ​ $ 38,958 ​ $ 72,967 ​ $ 74,626 Rental operating expenses ​ (11,518) ​ (20,651) ​ (22,867) Real estate taxes and insurance ​ (5,654) ​ (11,165) ​ (10,851) Depreciation and amortization ​ (11,929) ​ (26,552) ​ (26,927) Income from dispositions ​ $ 9,857 ​ $ 14,599 ​ $ 13,981 ​

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events
Subsequent Events	11. Subsequent Events ​ On January 10, 2022, the Company entered into a credit agreement for a new revolving line of credit for borrowings, at the Company’s election, of up to $217.5 million (the “BofA Revolver”), which may be borrowed, repaid and reborrowed from time to time until the maturity date on January 12, 2024. The Company has the right to request an extension of the maturity date, subject to acceptance by the lenders and satisfaction of certain other customary conditions. The BofA Revolver includes an accordion feature that allows the Company to request an increase in borrowing capacity to an amount not exceeding $750 million in the aggregate, subject to receipt of lender commitments and satisfaction of certain customary conditions. Effective simultaneously with the closing of the BofA Revolver on January 10, 2022, the Company terminated the Former BofA Revolver. The Former BofA Revolver would have matured by its own terms on January 12, 2022. ​ On January 12, 2022, the Company paid a special cash distribution of $0.32 per share of common stock, which was declared on December 3, 2021 for shareholders of record on December 31, 2021. ​ On January 14, 2022, the Board of Directors of the Company declared a cash distribution of $0.09 per share of common stock payable on February 17, 2022 to stockholders of record on January 28, 2022. ​ On February 10, 2022, the Company increased its BofA Revolver availability by $20.0 million to $237.5 million as part of the accordion feature that is available to increase borrowing capacity.

Schedule II Valuation and quali

Schedule II Valuation and qualifying accounts	12 Months Ended
	Dec. 31, 2021
Schedule II Valuation and qualifying accounts:
Schedule II Valuation and qualifying accounts:	​ ​ Schedule II ​ Franklin Street Properties Corp. Valuation and qualifying accounts: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Additions ​ ​ ​ ​ ​ ​ ​ (Decreases) ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ charged to ​ ​ ​ ​ Balance (in thousands) ​ beginning ​ costs and ​ ​ ​ ​ at end Classification ​ of year ​ expenses ​ Deductions ​ of year ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for doubtful accounts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 200 ​ $ 213 ​ $ (113) ​ $ 300 ​ 2020 ​ 300 ​ 340 ​ (135) ​ 505 ​ 2021 ​ 505 ​ 157 ​ (129) ​ 533 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Straight-line rent allowance for doubtful accounts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 50 ​ $ — ​ $ — ​ $ 50 ​ 2020 ​ 50 ​ — ​ (50) ​ — ​ 2021 ​ — ​ — ​ — ​ — ​ ​

SCHEDULE III REAL ESTATE AND AC

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION	12 Months Ended
	Dec. 31, 2021
SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION
SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION	SCHEDULE III FRANKLIN STREET PROPERTIES CORP. REAL ESTATE AND ACCUMULATED DEPRECIATION December 31, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Initial Cost ​ Historical Cost ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Costs ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Capitalized ​ ​ ​ ​ Buildings ​ ​ ​ ​ ​ ​ ​ Total Costs, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Buildings ​ (Disposals) ​ ​ ​ ​ Improvements ​ ​ ​ ​ ​ ​ ​ Net of ​ Depreciable ​ ​ ​ Date of ​ ​ Encumbrances ​ ​ ​ ​ Improvements ​ Subsequent to ​ ​ ​ ​ and ​ ​ ​ ​ Accumulated ​ Accumulated ​ Life ​ Year ​ Acquisition Description ​ (1) ​ Land ​ and Equipment ​ Acquisition ​ Land ​ Equipment ​ Total (2) ​ Depreciation ​ Depreciation ​ Years ​ Built ​ (3) ​ ​ (in thousands) Commercial Properties: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Forest Park, Charlotte, NC ​ — ​ $ 1,559 ​ $ 5,672 ​ $ 3,051 ​ $ 1,559 ​ $ 8,723 ​ $ 10,282 ​ 2,576 ​ $ 7,706 5 - 39 1999 1999 ​ Northwest Point, Elk Grove Village, IL — ​ 2,914 ​ 26,295 ​ 13,023 ​ 2,914 ​ 39,318 ​ 42,232 ​ 20,586 ​ 21,646 5 - 39 1999 2001 ​ Park Ten, Houston, TX — ​ 1,061 ​ 21,303 ​ 7,082 ​ 567 ​ 28,879 ​ 29,446 ​ 14,214 ​ 15,232 5 - 39 1999 2002 ​ Addison, Addison, TX — ​ 4,325 ​ 48,040 ​ 12,495 ​ 4,325 ​ 60,535 ​ 64,860 ​ 25,772 ​ 39,088 5 - 39 1999 2002 ​ Collins, Richardson, TX — ​ 4,000 ​ 42,598 ​ 8,804 ​ 4,000 ​ 51,402 ​ 55,402 ​ 24,755 ​ 30,647 5 - 39 1999 2003 ​ Greenwood, Englewood, CO — ​ 3,100 ​ 30,201 ​ 12,530 ​ 3,100 ​ 42,731 ​ 45,831 ​ 20,295 ​ 25,536 5 - 39 2000 2005 ​ Innsbrook, Glenn Allen, VA — ​ 5,000 ​ 40,216 ​ 9,002 ​ 5,000 ​ 49,218 ​ 54,218 ​ 20,578 ​ 33,640 5 - 39 1999 2003 ​ 380 Interlocken, Bloomfield, CO — ​ 8,275 ​ 34,462 ​ 13,194 ​ 8,275 ​ 47,656 ​ 55,931 ​ 19,130 ​ 36,801 5 - 39 2000 2003 ​ Blue Lagoon, Miami, FL — ​ 6,306 ​ 46,124 ​ 33,388 ​ 6,306 ​ 79,512 ​ 85,818 ​ 16,927 ​ 68,891 5 - 39 2002 2003 ​ Eldridge Green, Houston, TX — ​ 3,900 ​ 43,791 ​ 5,923 ​ 3,900 ​ 49,714 ​ 53,614 ​ 21,202 ​ 32,412 5 - 39 1999 2004 ​ Liberty Plaza, Addison, TX — ​ 4,374 ​ 21,146 ​ 10,542 ​ 4,374 ​ 31,688 ​ 36,062 ​ 13,172 ​ 22,890 5 - 39 1985 2006 ​ 390 Interlocken, Broomfield, CO — ​ 7,013 ​ 37,751 ​ 14,399 ​ 7,013 ​ 52,150 ​ 59,163 ​ 20,579 ​ 38,584 5 - 39 2002 2006 ​ Park Ten II, Houston, TX — ​ 1,300 ​ 31,712 ​ 7,245 ​ 1,300 ​ 38,957 ​ 40,257 ​ 13,458 ​ 26,799 5 - 39 2006 2006 ​ 121 South Eight Street, Minneapolis, MN — ​ 4,444 ​ 15,214 ​ 28,449 ​ 4,444 ​ 43,663 ​ 48,107 ​ 12,968 ​ 35,139 5 - 39 1974 2010 ​ 801 Marquette Ave South, Minneapolis, MN ​ — ​ 4,184 ​ — ​ 27,798 ​ 4,184 ​ 27,798 ​ 31,982 ​ 2,889 ​ 29,093 5 - 39 1923 2010 ​ 909 Davis, Evanston, IL — ​ 4,912 ​ 18,229 ​ 8,235 ​ 4,912 ​ 26,464 ​ 31,376 ​ 8,145 ​ 23,231 5 - 39 2002 2011 ​ Legacy Tennyson Center, Plano, TX — ​ 3,067 ​ 22,064 ​ 4,046 ​ 3,067 ​ 26,110 ​ 29,177 ​ 7,756 ​ 21,421 5 - 39 2008 2011 ​ One Legacy Circle, Plano, TX — ​ 2,590 ​ 36,608 ​ 4,822 ​ 2,590 ​ 41,430 ​ 44,020 ​ 11,945 ​ 32,075 5 - 39 2008 2011 ​ Westchase I & II, Houston, TX — ​ 8,491 ​ 121,508 ​ 17,044 ​ 8,491 ​ 138,552 ​ 147,043 ​ 33,721 ​ 113,322 5 - 39 2008 2012 ​ 1999 Broadway, Denver CO — ​ 16,334 ​ 137,726 ​ 39,108 ​ 16,334 ​ 176,834 ​ 193,168 ​ 40,105 ​ 153,063 5 - 39 1986 2013 ​ 1001 17th Street, Denver, CO — ​ 17,413 ​ 165,058 ​ 24,286 ​ 17,413 ​ 189,344 ​ 206,757 ​ 41,367 ​ 165,390 5 - 39 2006 2013 ​ Plaza Seven, Minneapolis, MN ​ — ​ 6,604 ​ 54,240 ​ 11,468 ​ 6,604 ​ 65,708 ​ 72,312 ​ 11,471 ​ 60,841 5 - 39 1987 2016 ​ Pershing Plaza, Atlanta, GA ​ — ​ 5,300 ​ 34,158 ​ 4,119 ​ 5,300 ​ 38,277 ​ 43,577 ​ 5,147 ​ 38,430 5 - 39 1989 2016 ​ 600 17th Street, Denver, CO ​ — ​ 20,876 ​ 99,941 ​ 14,005 ​ 20,876 ​ 113,946 ​ 134,822 ​ 15,729 ​ 119,093 5 - 39 1982 2016 ​ Balance — Real Estate — ​ $ 147,342 ​ $ 1,134,057 ​ $ 334,058 ​ $ 146,848 ​ $ 1,468,609 ​ $ 1,615,457 ​ $ 424,487 ​ $ 1,190,970 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) There are no encumbrances on the above properties. (2) The aggregate cost for Federal Income Tax purposes is $1,773,262 . (3) Original date of acquisition by Sponsored Entity. ​ ​ ​

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Significant Accounting Policies
Basis of Presentation	Basis of Presentation ​ The accompanying consolidated financial statements include all of the accounts of the Company and its majority-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.
Estimates and Assumptions	Estimates and Assumptions ​ The Company prepares its financial statements and related notes in conformity with generally accepted accounting principles in the United States of America (“GAAP”). These principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates in the consolidated financial statements include the allowance for doubtful accounts, allowance for credit losses, purchase price allocations, impairment considerations, useful lives of fixed assets and the valuation of derivatives.
Investments in non-consolidated REITs	Investments in non-consolidated REITs ​ As of December 31, 2021, the Company has a non-controlling common stock interest in two Sponsored REITs in which the Company no longer shares in economic benefit or risk. The Company had a non-controlling common stock interest in another Sponsored REIT and a non-controlling preferred stock interest in additional Sponsored REITs, each of which were liquidated during 2019 or 2018. The Company exercised influence over, but did not control these entities and investments were accounted for using the equity method. Under the equity method of accounting, the Company's cost basis was adjusted by its share of the Sponsored REITs' earnings or losses. ​ The equity investments in Sponsored REITS were reviewed for impairment each reporting period. The Company recorded impairment charges when events or circumstances indicated a decline in the fair value below the carrying value of the investment had occurred and such decline was other-than-temporary.
Variable Interest Entities	Variable Interest Entities (VIEs) ​ We determine whether an entity is a VIE and, if so, whether it should be consolidated by utilizing judgments and estimates that are inherently subjective. The determination of whether an entity in which we hold a direct or indirect variable interest is a VIE is based on several factors, including whether the entity’s total equity investment at risk upon inception is sufficient to finance the entity’s activities without additional subordinated financial support. We make judgments regarding the sufficiency of the equity at risk based first on a qualitative analysis, and then a quantitative analysis, if necessary. We analyze any investments in VIEs to determine if we are the primary beneficiary. In evaluating whether we are the primary beneficiary, we evaluate our direct and indirect economic interests in the entity. Determining which reporting entity, if any, is the primary beneficiary of a VIE is primarily a qualitative approach focused on identifying which reporting entity has both (1) the power to direct the activities of a VIE that most significantly impact such entity’s economic performance and (2) the obligation to absorb losses or the right to receive benefits from such entity that could potentially be significant to such entity. Performance of that analysis requires the exercise of judgment. ​ We consider a variety of factors in identifying the entity that holds the power to direct matters that most significantly impact the VIE’s economic performance including, but not limited to, the ability to direct a proposed sale of the property or merger of the company. In addition, we consider the rights of other investors to participate in those decisions, to replace the manager and to amend the corporate charter. We determine whether we are the primary beneficiary of a VIE at the time we become involved with a variable interest entity and reconsider that conclusion upon a reconsideration event. As of December 31, 2021, our relationship with FSP Monument Circle LLC was considered a VIE for which we are not the primary beneficiary. Our maximum exposure to losses associated with this VIE is limited to the outstanding Sponsored REIT Loan, the related accrued interest receivable and an exit fee receivable, which were in aggregate approximately $24.5 million at December 31, 2021. The accrued interest and exit fee receivables are included in prepaid expenses and other assets in the consolidated balance sheet and are approximately $0.5 million at December 31, 2021. The relationships and investments related to the entity in which we have a variable interest with are summarized in Note ​ 3, Related Party Transactions and Investments in Non-Consolidated Entities.
Real Estate and Depreciation	Real Estate and Depreciation ​ Real estate assets are stated at cost less accumulated depreciation. ​ The Company allocates the value of real estate acquired among land, buildings and identified intangible assets or liabilities. Costs related to land, building and improvements are capitalized. Typical capital items include new roofs, site improvements, various exterior building improvements and major interior renovations. Costs incurred in connection with leasing (primarily tenant improvements and leasing commissions) are capitalized and amortized over the lease period. Routine replacements and ordinary maintenance and repairs that do not extend the life of the asset are expensed as incurred. Depreciation is computed using the straight-line method over the assets’ estimated useful lives as follows: ​ ​ ​ ​ ​ ​ ​ Category Years Commercial buildings ​ 39 ​ ​ Building improvements 15 - 39 ​ Fixtures and equipment 3 - 7 ​ ​ The Company reviews its properties to determine if their carrying amounts will be recovered from future operating cash flows if certain indicators of impairment are identified at those properties. These indicators may include declining tenant occupancy, weak or declining tenant profitability, cash flows or liquidity, the Company’s decision to dispose of an asset before the end of its estimated useful life or legislative, economic, or market changes that permanently reduce the value of the Company’s investment. If indicators of impairment are present, the Company evaluates the carrying value of the property by comparing it to its expected future undiscounted cash flow. If the Company determines that impairment has occurred, the affected assets are reduced to their fair value. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Since cash flows are considered on an undiscounted basis in the analysis that the Company conducts to determine whether an asset has been impaired, the Company’s strategy of holding properties over the long term directly decreases the likelihood of recording an impairment loss. If the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized. The Company did not recognize any impairment losses for the years ended December 31, 2021, 2020 or 2019.
Acquired Real Estate Leases and Amortization	Acquired Real Estate Leases and Amortization ​ Acquired real estate leases represent costs associated with acquiring an in-place lease (i.e., the market cost to execute a similar lease, including leasing commission, tenant improvements, legal, vacancy and other related costs) and the value relating to leases with rents above the market rate. Amortization is computed using the straight-line method over the term of the leases, which range from 12 months to 154 months . Amortization of these combined components was approximately $8.2 million, $12.5 million and $18.9 million for the years ended December 31, 2021, 2020 and 2019, respectively. ​ Amortization related to costs associated with acquiring an in-place lease is included in depreciation and amortization on the consolidated statements of income. Amortization related to leases with rents above the market rate is offset against the rental revenue in the consolidated statements of income. The estimated annual amortization expense for the five years and thereafter following December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 ​ $ 3,882 ​ 2023 ​ 3,211 ​ 2024 ​ 2,870 ​ 2025 ​ 2,196 ​ 2026 ​ 1,789 ​ 2027 and thereafter ​ 986 ​
Acquired Unfavorable Real Estate Leases and Amortization	Acquired Unfavorable Real Estate Leases and Amortization ​ Acquired unfavorable real estate leases represent the value relating to leases with rents below the market rate. Amortization is computed using the straight-line method over the term of the leases, which range from 64 months to 151 months . Amortization expense was approximately $0.5 million, $0.9 million and $1.3 million for the years ended December 31, 2021, 2020 and 2019, respectively. ​ Amortization related to leases with rents below the market rate is included with rental revenue in the consolidated statements of income. The estimated annual amortization for the five years and thereafter following December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 ​ $ 161 ​ 2023 ​ 104 ​ 2024 ​ 93 ​ 2025 ​ 60 ​ 2026 ​ 31 ​ 2027 and thereafter ​ 79 ​
Assets held for sale	Asset Held For Sale ​ Classification of a property as held for sale typically occurs upon the execution of a purchase and sale agreement and belief by management that the sale or disposition is probable of occurrence within one year . Upon determining that a property was held for sale, the Company discontinues depreciating the property and reflects the property in its consolidated balance sheet at the lower of its carrying amount or fair value less the cost to sell. The Company presents the property held for sale on its consolidated balance sheet as “Asset held for sale”. The Company reports the results of operations of its properties sold or held for sale in its consolidated statements of income through the date of sale.
Cash and Cash Equivalents	Cash and Cash Equivalents ​ The Company considers all highly liquid instruments purchased with an original maturity of three months or less to be cash equivalents. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statement of cash flows. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 34,308 ​ $ 2,650 Restricted cash ​ 6,443 ​ 1,500 Total cash, cash equivalents and restricted cash ​ $ 40,751 ​ $ 4,150
Cash, Cash Equivalents and Restricted Cash	Restricted Cash ​ Restricted cash consists of tenant security deposits, which are required by law in some states or by contractual agreement to be kept in a segregated account, and escrows arising from property sales. Tenant security deposits are refunded when tenants vacate, provided that the tenant has not damaged the property. ​ Cash held in escrow is paid when the related issue is resolved. Restricted cash also may include funds segregated for specific tenant improvements per lease agreements.
Tenant Rent Receivables	Tenant Rent Receivables ​ Tenant rent receivables are expected to be collected within one year . The Company provided an allowance for doubtful accounts based on collectability. The Company recognizes the effect of a change in its assessment of whether the collectability of operating lease receivables are probable as an adjustment to lease income rather than bad debt expense.
Related Party Mortgage Loan Receivable	Related Party Mortgage Loan Receivable ​ Management monitors and evaluates the secured loans compared to the expected performance, cash flow and value of the underlying real estate and has not experienced a loss on these loans to date.
Concentration of Credit Risks	Concentration of Credit Risks ​ Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash investments, derivatives, related party mortgage loan receivable and accounts receivable. The Company maintains its cash balances principally in banks which the Company believes to be creditworthy. The Company periodically assesses the financial condition of the banks and believes that the risk of loss is minimal. Cash balances held with various financial institutions frequently exceed the insurance limit of provided by the Federal Deposit Insurance Corporation. The derivatives that the Company has are from interest rate swap agreements that are discussed in Note 5. The related party mortgage loan receivable is held with Sponsored REIT. The Company performs regular evaluations on the extent and impact of any credit deterioration that could affect the performance and value of the secured property, as well as the financial and operating capability of the borrower. The Company performs ongoing credit evaluations of its tenants and requires certain tenants to provide security deposits or letters of credit. Though these security deposits and letters of credit are insufficient to meet the total value of a tenant’s lease obligation, they are a measure of good faith and a source of funds to offset the economic costs associated with lost rent and the costs associated with re-tenanting the space. The Company has no single tenant which accounts for more than
Financial Instruments	Financial Instruments ​ The Company estimates that the carrying values of cash and cash equivalents, restricted cash, receivables, prepaid expenses, accounts payable and accrued expenses, accrued compensation, and tenant security deposits approximate their fair values based on their short-term maturity and the bank note and term loans payable approximate their fair values as they bear interest at variable interest rates.
Straight-line Rent Receivable	Straight-line Rent Receivable ​ Certain leases provide for fixed rent increases over the term of the lease. Rental revenue is recognized on a straight-line basis over the related lease term; however, billings by the Company are based on the lease agreements. Straight-line rent receivable, which is the cumulative revenue recognized in excess of amounts billed by the Company, was 31, 2021, 2020 and 2019, respectively. Prior to 2020, the Company provided an allowance for doubtful accounts based on collectability. The Company recognized the effect of a change in its assessment of whether the collectability of operating lease receivables are probable as an adjustment to lease income rather than bad debt expense. The reserve was eliminated during 2020 and no changes occurred during 2019 based on such assessment.
Deferred Leasing Commissions	Deferred Leasing Commissions ​ Deferred leasing commissions represent direct and incremental external leasing costs incurred in the leasing of commercial space. These costs are capitalized and are amortized on a straight-line basis over the terms of the related lease agreements. Amortization expense was approximately ​ The estimated annual amortization for the five years and thereafter following December 31, 2021 is as follows: ​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 $ 6,504 ​ 2023 6,081 ​ 2024 5,299 ​ 2025 4,377 ​ 2026 3,586 ​ 2027 and thereafter 12,464 ​
Common Share Repurchases	Common Share Repurchases ​ The Company recognizes the gross cost of the common shares it repurchases as a reduction in stockholders’ equity using the treasury stock method. Maryland law does not recognize a separate treasury stock account but provides that shares repurchased are classified as authorized but unissued shares. Accordingly, the Company reduces common stock for the par value and the excess of the purchase price over the par value is a reduction to additional paid-in capital.
Revenue Recognition	Revenue Recognition ​ Rental Revenue - The Company has retained substantially all of the risks and benefits of ownership of the Company’s commercial properties and accounts for its leases as operating leases. Rental revenue includes income from leases, certain reimbursable expenses, straight-line rent adjustments and other income associated with renting the property. Rental income from leases, which includes rent concessions (including free rent and other lease inducements) and scheduled increases in rental rates during the lease term, is recognized on a straight-line basis. The Company does not have any significant percentage rent arrangements with its commercial property tenants. Reimbursable expenses are included in rental income in the period earned. A summary of rental revenue is shown in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, (in thousands) 2021 2020 2019 Income from leases ​ $ 148,705 ​ $ 180,899 ​ $ 191,828 ​ Reimbursable expenses ​ 54,825 ​ 61,310 ​ 64,421 ​ Straight-line rent adjustment ​ 4,017 ​ 1,685 ​ 8,876 ​ Amortization of favorable and unfavorable leases ​ 34 ​ 313 ​ 402 ​ ​ ​ $ 207,581 ​ $ 244,207 ​ $ 265,527 ​
Rental Revenue	Rental Revenue - The Company has retained substantially all of the risks and benefits of ownership of the Company’s commercial properties and accounts for its leases as operating leases. Rental revenue includes income from leases, certain reimbursable expenses, straight-line rent adjustments and other income associated with renting the property. Rental income from leases, which includes rent concessions (including free rent and other lease inducements) and scheduled increases in rental rates during the lease term, is recognized on a straight-line basis. The Company does not have any significant percentage rent arrangements with its commercial property tenants. Reimbursable expenses are included in rental income in the period earned. A summary of rental revenue is shown in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, (in thousands) 2021 2020 2019 Income from leases ​ $ 148,705 ​ $ 180,899 ​ $ 191,828 ​ Reimbursable expenses ​ 54,825 ​ 61,310 ​ 64,421 ​ Straight-line rent adjustment ​ 4,017 ​ 1,685 ​ 8,876 ​ Amortization of favorable and unfavorable leases ​ 34 ​ 313 ​ 402 ​ ​ ​ $ 207,581 ​ $ 244,207 ​ $ 265,527 ​
Related Party and Other Revenue	Related Party and Other Revenue -
Segment Reporting	Segment Reporting ​ The Company is a REIT focused on real estate investments primarily in the office market and currently operates in only one segment: real estate operations.
Income Taxes	Income Taxes ​ Taxes on income for the years ended December 31, 2021, 2020 and 2019 represent taxes incurred by FSP Protective TRS Corp, which is a taxable REIT subsidiary, and the State of Texas franchise tax applicable to FSP Corp., which is classified as an income tax for reporting purposes.
Net Income Per Share	Net Income Per Share ​ Basic net income per share is computed by dividing net income by the weighted average number of shares outstanding during the period. Diluted net income per share reflects the potential dilution that could occur if securities or other contracts to issue shares were exercised or converted into shares. There were
Derivative Instruments	Derivative Instruments ​ The Company recognizes derivatives on the consolidated balance sheets at fair value. Derivatives that do not qualify, or are not designated as hedge relationships, must be adjusted to fair value through income. Derivative instruments designated in a hedge relationship to mitigate exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Cash flow hedges are accounted for by recording the fair value of the derivative instrument on the consolidated balance sheets as either an asset or liability. To the extent hedges are effective, a corresponding amount, adjusted for swap payments, is recorded in accumulated other comprehensive income within stockholders’ equity. Amounts are then reclassified from accumulated other comprehensive income to the income statement in the period or periods the hedged forecasted transaction affects earnings. Ineffectiveness, if any, is recognized in other comprehensive income (“OCI”) and reclassified into the income statement. The Company reviews the effectiveness of each hedging transaction, which involves estimating future cash flows, at least quarterly. Derivative instruments designated in a hedge relationship to mitigate exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. The Company currently has
Fair Value Measurements	Fair Value Measurements ​ Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. There is also an established fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value. Financial assets and liabilities recorded on the consolidated balance sheets at fair value are categorized based on the inputs to the valuation techniques as follows: ​ Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, which is typically based on an entity’s own assumptions, as there is little, if any, related market activity or information. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability including credit risk, which was not significant to the overall value. These inputs (See Notes 3 and 5) were considered and applied to the Company’s derivative instruments and Sponsored REIT Loan. Level 2 inputs were used to value the interest rate swaps and Level 3 inputs were used to value the Sponsored REIT Loan.
Subsequent Events	Subsequent Events ​ In preparing these consolidated financial statements the Company evaluated events that occurred through the date of issuance of these financial statements for potential recognition or disclosure.
Recent Accounting Standards	Recent Accounting Standards ​ In March 2020, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). ASU 2020-04 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-04 is optional and may be elected over time as reference rate reform activities occur. The Company is currently assessing the potential impact that the adoption of ASU 2020-04 may have on its consolidated financial statements.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Significant Accounting Policies
Schedule of estimated useful lives of real estate assets	​ ​ ​ ​ ​ ​ ​ Category Years Commercial buildings ​ 39 ​ ​ Building improvements 15 - 39 ​ Fixtures and equipment 3 - 7 ​
Schedule of estimated annual amortization expense for succeeding five years for acquired in-place lease and above-market leases	​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 ​ $ 3,882 ​ 2023 ​ 3,211 ​ 2024 ​ 2,870 ​ 2025 ​ 2,196 ​ 2026 ​ 1,789 ​ 2027 and thereafter ​ 986 ​
Schedule of estimated annual amortization for unfavorable leases	​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 ​ $ 161 ​ 2023 ​ 104 ​ 2024 ​ 93 ​ 2025 ​ 60 ​ 2026 ​ 31 ​ 2027 and thereafter ​ 79 ​
Schedule of Cash and cash equivalents	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) ​ 2021 ​ 2020 Cash and cash equivalents ​ $ 34,308 ​ $ 2,650 Restricted cash ​ 6,443 ​ 1,500 Total cash, cash equivalents and restricted cash ​ $ 40,751 ​ $ 4,150
Schedule of estimated annual amortization for deferred leasing commissions	​ ​ ​ ​ ​ ​ (in thousands) December 31, 2022 $ 6,504 ​ 2023 6,081 ​ 2024 5,299 ​ 2025 4,377 ​ 2026 3,586 ​ 2027 and thereafter 12,464 ​
Summary of rental revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, (in thousands) 2021 2020 2019 Income from leases ​ $ 148,705 ​ $ 180,899 ​ $ 191,828 ​ Reimbursable expenses ​ 54,825 ​ 61,310 ​ 64,421 ​ Straight-line rent adjustment ​ 4,017 ​ 1,685 ​ 8,876 ​ Amortization of favorable and unfavorable leases ​ 34 ​ 313 ​ 402 ​ ​ ​ $ 207,581 ​ $ 244,207 ​ $ 265,527 ​

Related Party Transactions an_2

Related Party Transactions and Investments in Non-Consolidated Entities (Tables)	12 Months Ended
	Dec. 31, 2021
Related Party Transactions and Investments in Non-Consolidated Entities
Schedule of equity in losses of investments in non-consolidated REITs	​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ ​ ​ December 31, ​ (in thousands) 2021 ​ ​ ​ ​ Equity in income of East Wacker ​ $ 421 ​ Total ​ $ 421 ​
Schedule of distributions received from non-consolidated REITs	​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ ​ ​ December 31, ​ (in thousands) 2021 ​ ​ ​ ​ ​ Distributions from East Wacker ​ $ 421 ​ ​ ​ $ 421 ​
Summary of the Sponsored REIT Loans outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Maximum Amount Interest (dollars in thousands, except footnotes) ​ ​ Maturity ​ Amount ​ Outstanding Rate at Sponsored REIT Location ​ Date ​ of Loan ​ 31-Dec-21 31-Dec-21 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mortgage loan secured by property ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ FSP Monument Circle LLC (1) ​ Indianapolis, IN ​ 30-Jun-23 ​ $ 24,000 ​ $ 24,000 7.51 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 24,000 ​ $ 24,000 ​ ​ (1) This mortgage loan includes an origination fee of $164,000 and an exit fee of $38,000 when repaid by the borrower.

Bank Note Payable, Term Note _2

Bank Note Payable, Term Note Payable and Private Placements (Tables)	12 Months Ended
	Dec. 31, 2021
BAML Revolver
Debt Instrument [Line Items]
Schedule of actual amount of applicable facility fee, LIBOR rate or base rate determined based on total leverage ratio	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Base ​ ​ ​ ​ ​ LIBOR Rate ​ Facility ​ Rate ​ Level Credit Rating Margin Fee Margin I A- / A3 (or higher) 0.825 % 0.125 % 0.000 % II BBB+ / Baa1 ​ 0.875 % 0.150 % 0.000 % III BBB / Baa2 ​ 1.000 % 0.200 % 0.000 % IV BBB- / Baa3 ​ 1.200 % 0.250 % 0.200 % V <BBB- / Baa3 ​ 1.550 % 0.300 % 0.550 %
BAML Term Loan
Debt Instrument [Line Items]
Schedule of actual amount of applicable facility fee, LIBOR rate or base rate determined based on total leverage ratio	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ LIBOR Rate ​ Base Rate ​ Level Credit Rating Margin Margin I A- / A3 (or higher) 0.900 % 0.000 % II BBB+ / Baa1 ​ 0.950 % 0.000 % III BBB / Baa2 ​ 1.100 % 0.100 % IV BBB- / Baa3 ​ 1.350 % 0.350 % V <BBB- / Baa3 ​ 1.750 % 0.750 %
BMO Term Loan
Debt Instrument [Line Items]
Schedule of actual amount of applicable facility fee, LIBOR rate or base rate determined based on total leverage ratio	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Credit ​ LIBOR Rate ​ Base Rate ​ Level Rating Margin Margin I ​ A- / A3 (or higher) ​ 85.0 bps — bps II ​ BBB+ / Baa1 ​ ​ 90.0 bps — bps III ​ BBB / Baa2 ​ ​ 100.0 bps — bps IV ​ BBB- / Baa3 ​ ​ 125.0 bps 25.0 bps V ​ <BBB- / Baa3 ​ ​ 165.0 bps 65.0 bps

Financial Instruments_ Deriva_2

Financial Instruments: Derivatives and Hedging (Tables)	12 Months Ended
	Dec. 31, 2021
Financial Instruments: Derivatives and Hedging
Schedule of notional and fair value of derivative financial instruments	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Notional Strike Effective Expiration Fair Value (2) at (in thousands) ​ Value ​ Rate ​ Date ​ Date ​ December 31, 2021 December 31, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2017 Interest Rate Swap ​ $ 400,000 1.12 % Sep-17 Sep-21 ​ $ — ​ $ (2,947) ​ 2019 JPM Interest Rate Swap ​ $ 100,000 2.44 % Mar-19 Nov-21 ​ $ — ​ $ (2,102) ​ 2019 BMO Interest Rate Swap (1) ​ $ 165,000 2.39 % Aug-20 Jan-24 ​ $ (5,239) ​ $ (12,262) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The Notional Value decreased to $165 million on June 4, 2021. ​ (2) Classified within Level 2 of the fair value hierarchy. ​
Summary of Interest Rate Swaps that was recorded in OCI	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ Year Ended December 31, Interest Rate Swaps in Cash Flow Hedging Relationships: 2021 2020 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts of gain (loss) recognized in OCI ​ $ 3,786 ​ $ (20,380) ​ $ (15,119) Amounts of previously recorded gain/(loss) reclassified from OCI into Interest Expense ​ $ (8,286) ​ $ (7,751) ​ $ 4,328 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total amount of Interest Expense presented in the consolidated statements of operations ​ $ 32,273 ​ $ 36,026 ​ $ 36,757

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity
Schedule of Share-based Payment Arrangement, Nonemployee Director Award Plan, Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ Shares Available ​ Compensation ​ ​ for Grant ​ Cost ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2018 ​ ​ 1,944,428 ​ $ — Shares granted 2019 ​ ​ (38,046) ​ ​ 337,500 Balance December 31, 2019 ​ ​ 1,906,382 ​ $ 337,500 Shares granted 2020 ​ ​ (58,998) ​ ​ 337,500 Balance December 31, 2020 ​ ​ 1,847,384 ​ $ 675,000 Shares granted 2021 ​ ​ (66,564) ​ ​ 337,500 Balance December 31, 2021 ​ ​ 1,780,820 ​ $ 1,012,500 ​ ​ ​ ​ ​ ​ ​
Schedule of repurchase of common stock	​ ​ ​ ​ ​ ​ ​ ​ (Cost in thousands) ​ ​ Shares Repurchased ​ Cost Balance December 31, 2020 ​ 1,017,498 $ 18,775 Repurchase of shares ​ ​ 3,396,243 ​ ​ 18,244 Balance, December 31, 2021 ​ ​ 4,413,741 ​ $ 37,019

Federal Income Tax Reporting (T

Federal Income Tax Reporting (Tables)	12 Months Ended
	Dec. 31, 2021
Federal Income Tax Reporting
Schedule of income tax expense reflected in the condensed consolidated statements of income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, (Dollars in thousands) 2021 2020 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revised Texas Franchise Tax ​ $ 234 ​ $ 250 ​ $ 394 ​ Other Taxes ​ 404 ​ — ​ (125) ​ Tax expense ​ $ 638 ​ $ 250 ​ $ 269 ​
Summary of tax components of Company's common distribution paid per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2021 ​ 2020 ​ 2019 ​ Per Share % Per Share % Per Share % Ordinary income (1) ​ $ — — % $ 0.28 77.51 % $ 0.25 69.96 % Capital gain ​ 0.68 100 % 0.06 16.72 % — — % Return of capital ​ — — % 0.02 5.77 % 0.11 30.04 % Total ​ $ 0.68 100 % $ 0.36 100 % $ 0.36 100 %

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases
Summary of lease costs and maturity analysis for liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Lease Costs ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended (in thousands) ​ December 31, 2021 ​ December 31, 2020 ​ December 31, 2019 Operating lease cost $ 419 ​ $ 419 ​ $ 419 ​ $ 419 ​ $ 419 ​ $ 419 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities ​ 429 ​ ​ 421 ​ ​ 412 Weighted average remaining lease terms in years - operating leases ​ 2.75 ​ ​ 3.75 ​ ​ 4.75 Weighted average discount rate - operating leases ​ 3.86% ​ ​ 3.86% ​ ​ 3.86% ​ ​ ​ ​ ​ ​ ​ ​ ​ Maturity analysis for liabilities Total ​ ​ ​ ​ ​ Undiscounted ​ ​ ​ ​ ​ ​ (in thousands) Cash Flows ​ ​ ​ ​ ​ ​ Discount rate at commencement ​ 3.86% ​ ​ ​ ​ ​ ​ 2022 ​ 438 ​ ​ ​ ​ ​ ​ 2023 ​ 447 ​ ​ ​ ​ ​ ​ 2024 ​ 340 ​ ​ ​ ​ ​ ​ ​ $ 1,225 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Present value lease liability $ 1,159 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Difference between undiscounted cash flows and discounted cash flows $ 66 ​ ​ ​ ​ ​ ​
Summary of income relating to lease payments and undiscounted cash flows	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income relating to lease payments: ​ ​ ​ ​ Year Ended (in thousands) December 31, 2021 ​ December 31, 2020 December 31, 2019 Income from leases (1) ​ $ 203,530 ​ $ 242,209 ​ $ 256,250 ​ ​ $ 203,530 ​ $ 242,209 ​ $ 256,250 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Undiscounted Cash Flows Year ending ​ ​ ​ ​ ​ ​ (in thousands) ​ December 31, ​ ​ ​ ​ ​ ​ 2022 ​ ​ 100,269 ​ ​ ​ ​ ​ ​ 2023 ​ ​ 103,107 ​ ​ ​ ​ ​ ​ 2024 ​ ​ 97,792 ​ ​ ​ ​ ​ ​ 2025 ​ ​ 83,596 ​ ​ ​ ​ ​ ​ 2026 ​ ​ 70,718 ​ ​ ​ ​ ​ ​ 2027 and thereafter ​ 259,673 ​ ​ ​ ​ ​ ​ ​ ​ $ 715,155 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Amounts recognized from variable lease payments were $54,825, $61,310 and $64,421 for the years ended December 31, 2021, 2020 and 2019, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​

Dispositions of property (Table

Dispositions of property (Tables)	12 Months Ended
	Dec. 31, 2021
Dispositions of property
Summary of operating results for discontinued operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended ​ ​ December 31, (in thousands) 2021 2020 ​ 2019 Rental revenue ​ $ 38,958 ​ $ 72,967 ​ $ 74,626 Rental operating expenses ​ (11,518) ​ (20,651) ​ (22,867) Real estate taxes and insurance ​ (5,654) ​ (11,165) ​ (10,851) Depreciation and amortization ​ (11,929) ​ (26,552) ​ (26,927) Income from dispositions ​ $ 9,857 ​ $ 14,599 ​ $ 13,981

Organization (Details)

Organization (Details)	12 Months Ended
	Dec. 31, 2021entityproperty
Organization
Number of REITs in which the entity holds non-controlling common stock interest	2
Number of Sponsored REITs	2
Number of promissory notes secured by mortgages on real estate owned by Sponsored REITs	1
Properties
Number of properties | property	24
FSP Investments LLC
Organization
Ownership interest (as a percent)	100.00%
FSP Property Management LLC
Organization
Ownership interest (as a percent)	100.00%
FSP Holdings LLC
Organization
Ownership interest (as a percent)	100.00%
FSP Protective TRS Corp.
Organization
Ownership interest (as a percent)	100.00%

Significant Accounting Polici_4

Significant Accounting Policies - Basis, Estimates and Inv in non-consolidated REITs (Detail)	Dec. 31, 2021entity
Significant Accounting Policies
Number of corporations organized to operate as real estate investment trusts (REITs)	2
Number of REITs in which the entity holds non-controlling preferred stock interest	2

Significant Accounting Polici_5

Significant Accounting Policies - Variable Interest Entities (Details) - VIE, Not Primary Beneficiary $ in Millions	Dec. 31, 2021USD ($)
Variable interest entity
Maximum exposure to losses associated with VIE	$ 24.5
Prepaid expenses and other assets
Variable interest entity
Accrued interest and exit fee receivables	$ 0.5

Significant Accounting Polici_6

Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2021
Commercial buildings
Real Estate and Depreciation
Estimated useful life	39 years
Building improvements | Minimum
Real Estate and Depreciation
Estimated useful life	15 years
Building improvements | Maximum
Real Estate and Depreciation
Estimated useful life	39 years
Fixtures and equipment | Minimum
Real Estate and Depreciation
Estimated useful life	3 years
Fixtures and equipment | Maximum
Real Estate and Depreciation
Estimated useful life	7 years

Significant Accounting Polici_7

Significant Accounting Policies - Acquired Real Estate Leases and Amortization (Details) - Acquired in-place and above market real estate leases - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Acquired real estate leases and amortization
Amortization expense	$ 8,200	$ 12,500	$ 18,900
Estimated annual amortization for succeeding five years
2022	3,882
2023	3,211
2024	2,870
2025	2,196
2026	1,789
2027 and thereafter	$ 986
Minimum
Acquired real estate leases and amortization
Term of lease	12 months
Maximum
Acquired real estate leases and amortization
Term of lease	154 months

Significant Accounting Polici_8

Significant Accounting Policies - Acquired Unfavorable Real Estate Leases and Amortization (Details) - Acquired unfavorable real estate leases - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Acquired Unfavorable Real Estate Leases and Amortization
Amortization	$ 500	$ 900	$ 1,300
Estimated annual amortization for succeeding five years
2022	161
2023	104
2024	93
2025	60
2026	31
2027 and thereafter	$ 79
Minimum
Acquired Unfavorable Real Estate Leases and Amortization
Term of lease	64 months
Maximum
Acquired Unfavorable Real Estate Leases and Amortization
Term of lease	151 months

Significant Accounting Polici_9

Significant Accounting Policies - Asset Held For Sale and Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Discontinued Operations
Time period within which sale or disposition of properties held for sale is probable	1 year
Cash, Cash Equivalents and Restricted Cash
Cash and cash equivalents	$ 34,308	$ 2,650
Restricted cash	6,443	1,500
Total cash, cash equivalents and restricted cash	$ 40,751	$ 4,150	$ 9,790	$ 11,177

Significant Accounting Polic_10

Significant Accounting Policies - Rent Receivables (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tenant Rent Receivables and Straight-line Rent Receivable
Period within which tenant rent receivables are expected to be collected	1 year
Straight-line rent receivable	$ 49	$ 67.8	$ 66.9

Significant Accounting Polic_11

Significant Accounting Policies - Concentration of Credit Risks (Details)	12 Months Ended
	Dec. 31, 2021USD ($)itementity
Concentration of Credit Risks
Number of banks in which the entity maintains cash balances	2
Number of interest rate swap agreements	3
Number of Sponsored REITs with which the related party mortgage loan receivable is held | entity	1
Cash balances with financial institutions | Credit concentration risk | Minimum
Concentration of Credit Risks
Insurance limit provided by Federal Deposit Insurance Corporation | $	$ 250,000
Annualized rental revenues | Single tenant rental revenues | Major tenants
Concentration of Credit Risks
Percentage of annualized rental revenues required for qualification as major tenant	10.00%

Significant Accounting Polic_12

Significant Accounting Policies - Deferred Leasing Commissions and Revenue Recognition (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)itemshares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares
Deferred Leasing Commissions
Amortization expense of deferred leasing commissions	$ 10,700	$ 9,600	$ 9,900
Estimated annual amortization of deferred leasing commissions for the succeeding five years
2022	6,504
2023	6,081
2024	5,299
2025	4,377
2026	3,586
2027 and thereafter	12,464
Summary of rental revenue
Income from leases	148,705	180,899	191,828
Reimbursable expenses	54,825	61,310	64,421
Straight line rent adjustments	4,017	1,685	8,876
Amortization of favorable and unfavorable leases	34	313	402
Total	$ 207,581	$ 244,207	$ 265,527
Segment Reporting
Number of reporting segments | item	1
Net Income Per Share
Potential dilutive shares outstanding | shares	0	0	0
Denominator used for calculating basic and diluted net income per share (in shares) | shares	106,667,000	107,303,000	107,233,000
Derivative instruments
Fair value hedges outstanding	$ 0
Rental
Summary of rental revenue
Total	$ 207,581	$ 244,207	$ 265,527

Related Party Transactions an_3

Related Party Transactions and Investments in Non-Consolidated Entities - Investment in Sponsored REITs (Details)	Dec. 31, 2021entity
Related Party Transactions and Investments in Non-Consolidated Entities
Number of REITs in which the entity holds non-controlling common stock interest	2
Number of REITs in which the entity holds non-controlling preferred stock interest	2

Related Party Transactions an_4

Related Party Transactions and Investments in Non-Consolidated Entities - Investment in Sponsored REITs - Property Sold (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
FSP Energy Tower I Corp.
Investment in Sponsored REITs
Repayment of principal	$ 51

Related Party Transactions an_5

Related Party Transactions and Investments in Non-Consolidated Entities - Equity in losses of investment in non-consolidated REITs (Details) - USD ($) $ in Thousands	Oct. 06, 2021	Dec. 31, 2007	Dec. 31, 2021	Dec. 31, 2019
Sponsored REITs
Equity in income (loss)			$ 421
Proceeds received from liquidating trust				$ 1,470
Distributions received from non-consolidated REITs
Distributions from non-consolidated REITs			421
East Wacker
Sponsored REITs
Equity in income (loss)	$ 400		421
Preferred shares purchased		965.75
Percentage of outstanding preferred shares purchased		43.70%
Distributions received from non-consolidated REITs
Distributions from non-consolidated REITs			$ 421

Related Party Transactions an_6

Related Party Transactions and Investments in Non-Consolidated Entities - Management fees and interest income from loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Sponsored REITs
Asset management fees, low end of range (as a percent)	1.00%
Asset management fees, high end of range (as a percent)	5.00%
Notice period for cancellation of applicable contracts	30 days
Type of revenue	Asset management fees	Asset management fees	Asset management fees
Impairment of Sponsored REIT	$ 0
Asset management fees
Sponsored REITs
Revenue	$ 100,000	$ 100,000	$ 200,000

Related Party Transactions an_7

Related Party Transactions and Investments in Non-Consolidated Entities - Sponsored REIT Loans outstanding (Details)	Dec. 06, 2020	Dec. 31, 2021USD ($)item	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Oct. 29, 2021USD ($)	Oct. 28, 2021USD ($)	Dec. 05, 2020
Sponsored REITs
Maximum amount of loan		$ 24,000,000
Amount Drawn		24,000,000	$ 21,000,000		$ 24,000,000	$ 21,000,000
Interest income and fees from the Sponsored REIT Loans		1,600,000	1,500,000	$ 3,300,000
Related party mortgage loan receivable		$ 24,000,000	$ 21,000,000		24,000,000	$ 21,000,000
Number of additional commitments to lend | item		0
Sponsored REITs
Sponsored REITs
Term of sponsored REIT loan secured by mortgage, minimum		1 year
Term of sponsored REIT loan secured by mortgage, maximum		3 years
FSP Monument Circle LLC
Sponsored REITs
Additional loan amount					$ 3,000,000
Mortgage loan | Sponsored REITs
Sponsored REITs
Interest rate (as a percent)	7.51%						7.19%
Mortgage Loan On Real Estate, Extended Term	2 years
Mortgage loan | Sponsored REITs | Fair Value, Inputs, Level 3 [Member]
Sponsored REITs
Amount Drawn		$ 23,800,000
Related party mortgage loan receivable		23,800,000
Mortgage loan | FSP Monument Circle LLC
Sponsored REITs
Maximum amount of loan		24,000,000
Amount Drawn		$ 24,000,000
Interest rate (as a percent)		7.51%
Origination fee		$ 164,000
Exit fee		38,000
Related party mortgage loan receivable		$ 24,000,000

Bank Note Payable, Term Note _3

Bank Note Payable, Term Note Payable and Private Placements (Details)

Oct. 25, 2021USD ($)

Sep. 30, 2021USD ($)

Jun. 04, 2021USD ($)

Dec. 24, 2020USD ($)

Oct. 24, 2017USD ($)

Dec. 31, 2021USD ($)

Dec. 31, 2020USD ($)

Dec. 23, 2020USD ($)

Mar. 29, 2019USD ($)

Mar. 07, 2019USD ($)

Sep. 27, 2018USD ($)

Aug. 02, 2018USD ($)

Oct. 18, 2017USD ($)

Debt Instrument [Line Items]

Repayments of unsecured debt

$ 445,000,000

$ 50,000,000

Loss on extinguishment of debt

(901,000)

Unsecured term loan

274,286,000

717,323,000

Portion of future LIBOR-based rate risk

5,200,000

Total available

$ 600,000,000

Borrowings outstanding

$ 3,500,000

Senior Notes

Debt Instrument [Line Items]

Principal amount of loan

$ 200,000,000

Fixed charge coverage ratio

1.50

Series A Notes

Debt Instrument [Line Items]

Principal amount of loan

$ 116,000,000

Interest rate (as a percent)

4.49%

Series B Notes

Debt Instrument [Line Items]

Principal amount of loan

$ 84,000,000

Interest rate (as a percent)

4.76%

Maximum | Senior Notes

Debt Instrument [Line Items]

Unsecured leverage ratio

60.00%

Unsecured leverage ratio for significant acquisition

65.00%

2012 Revolver | Federal Funds Rate

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.50%

2012 Revolver | One month LIBOR

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.00%

BAML Revolver

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

0.30%

Weighted average interest rate (as a percent)

1.33%

1.65%

Effective interest rate (as a percent)

1.65%

Total available

$ 600,000,000

Borrowings outstanding

$ 0

$ 3,500,000

BAML Revolver | A- | A3 | Minimum

Debt Instrument [Line Items]

Facility fee (as a percent)

0.125%

BAML Revolver | BBB+ | Baa1

Debt Instrument [Line Items]

Facility fee (as a percent)

0.15%

BAML Revolver | BBB | Baa2

Debt Instrument [Line Items]

Facility fee (as a percent)

0.20%

BAML Revolver | BBB- | Baa3

Debt Instrument [Line Items]

Facility fee (as a percent)

0.25%

BAML Revolver | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Facility fee (as a percent)

0.30%

BAML Revolver | LIBOR

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

1.55%

BAML Revolver | LIBOR | A- | A3 | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.825%

BAML Revolver | LIBOR | BBB+ | Baa1

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.875%

BAML Revolver | LIBOR | BBB | Baa2

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.00%

BAML Revolver | LIBOR | BBB- | Baa3

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.20%

BAML Revolver | LIBOR | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.55%

BAML Revolver | Bank's base rate

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

0.55%

BAML Revolver | Bank's base rate | A- | A3 | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.00%

BAML Revolver | Bank's base rate | BBB+ | Baa1

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.00%

BAML Revolver | Bank's base rate | BBB | Baa2

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.00%

BAML Revolver | Bank's base rate | BBB- | Baa3

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.20%

BAML Revolver | Bank's base rate | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.55%

BAML Term Loan

Debt Instrument [Line Items]

Principal amount of loan

$ 400,000,000

Repayments of unsecured debt

$ 200,000,000

$ 90,000,000

Loss on extinguishment of debt

$ (700,000)

Unsecured term loan

$ 110,000,000

Weighted average interest rate (as a percent)

1.85%

Effective interest rate (as a percent)

1.84%

Maximum borrowing capacity allowed by exercising an accordion feature

$ 500,000,000

BAML Term Loan | Federal Funds Rate

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.50%

BAML Term Loan | LIBOR

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

1.75%

Fixed rate (as a percent)

1.12%

BAML Term Loan | LIBOR | A- | A3 | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.90%

BAML Term Loan | LIBOR | BBB+ | Baa1

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.95%

BAML Term Loan | LIBOR | BBB | Baa2

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.10%

BAML Term Loan | LIBOR | BBB- | Baa3

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.35%

BAML Term Loan | LIBOR | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.75%

BAML Term Loan | Bank's base rate

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

0.75%

BAML Term Loan | Bank's base rate | A- | A3 | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.00%

BAML Term Loan | Bank's base rate | BBB+ | Baa1

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.00%

BAML Term Loan | Bank's base rate | BBB | Baa2

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.10%

BAML Term Loan | Bank's base rate | BBB- | Baa3

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.35%

BAML Term Loan | Bank's base rate | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.75%

BAML Term Loan | One month LIBOR

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.00%

JPM Term Loan

Debt Instrument [Line Items]

Principal amount of loan

$ 150,000,000

Repayments of unsecured debt

$ 100,000,000

$ 50,000,000

Loss on extinguishment of debt

(100,000)

Unsecured term loan

$ 100,000,000

Portion of future LIBOR-based rate risk

$ 100,000,000

JPM Term Loan | Hedged portion

Debt Instrument [Line Items]

Payment to terminate interest rate swap

1,200,000

Portion of future LIBOR-based rate risk

$ 100,000,000

$ 100,000,000

JPM Term Loan | LIBOR | Hedged portion

Debt Instrument [Line Items]

Fixed rate (as a percent)

2.44%

BMO Term Loan

Debt Instrument [Line Items]

Principal amount of loan

$ 220,000,000

Additional loans allowed by exercising an accordion feature

$ 100,000,000

Effective interest rate (as a percent)

4.04%

BMO Term Loan | Federal Funds Rate

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

0.50%

BMO Term Loan | LIBOR

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

1.65%

Fixed rate (as a percent)

2.32%

BMO Term Loan | LIBOR | Hedged portion

Debt Instrument [Line Items]

Fixed rate (as a percent)

2.39%

BMO Term Loan | LIBOR | A- | A3 | Minimum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

85.00%

BMO Term Loan | LIBOR | BBB+ | Baa1

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

90.00%

BMO Term Loan | LIBOR | BBB | Baa2

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

100.00%

BMO Term Loan | LIBOR | BBB- | Baa3

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

125.00%

BMO Term Loan | LIBOR | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

165.00%

BMO Term Loan | Bank's base rate

Debt Instrument [Line Items]

Basis spread on variable rate at period end (as a percent)

0.65%

BMO Term Loan | Bank's base rate | BBB- | Baa3

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

25.00%

BMO Term Loan | Bank's base rate | BBB- | Baa3 | Maximum

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

65.00%

BMO Term Loan | One month LIBOR

Debt Instrument [Line Items]

Basis spread on variable rate (as a percent)

1.00%

Tranche A Term Loan

Debt Instrument [Line Items]

Principal amount of loan

$ 55,000,000

Loss on extinguishment of debt

(100,000)

Payment to terminate interest rate swap

$ 600,000

Tranche B Term Loan

Debt Instrument [Line Items]

Principal amount of loan

$ 165,000,000

Financial Instruments_ Deriva_3

Financial Instruments: Derivatives and Hedging (Details) - USD ($) $ in Thousands	Jun. 04, 2021	Dec. 31, 2021	Dec. 31, 2020
Financial Instruments: Derivatives and Hedging
Hedged amount of portion of the future LIBOR-based rate risk		$ 5,200
Interest reclassified from accumulated other comprehensive income into interest expense		1,900
Amount estimated to be reclassified into earnings within next 12 months		2,500
JPM Term Loan
Financial Instruments: Derivatives and Hedging
Hedged amount of portion of the future LIBOR-based rate risk		100,000
2017 Interest Rate Swap | Cash flow hedges
Financial Instruments: Derivatives and Hedging
Notional Value		$ 400,000
Strike Rate (as a percent)		1.12%
Fair Value			$ (2,947)
2019 JPM Interest Rate Swap
Financial Instruments: Derivatives and Hedging
Payment to terminate interest rate swap	$ 1,200
2019 JPM Interest Rate Swap | Cash flow hedges
Financial Instruments: Derivatives and Hedging
Notional Value		$ 100,000
Strike Rate (as a percent)		2.44%
Fair Value			(2,102)
2019 BMO Interest Rate Swap
Financial Instruments: Derivatives and Hedging
Payment to terminate interest rate swap	600
2019 BMO Interest Rate Swap | Cash flow hedges
Financial Instruments: Derivatives and Hedging
Notional Value	$ 165,000	$ 165,000
Strike Rate (as a percent)		2.39%
Fair Value		$ (5,239)	$ (12,262)

Financial Instruments_ Deriva_4

Financial Instruments: Derivatives and Hedging - Interest Rate Swaps (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amount of Interest Expense presented in the consolidated statements of operations	$ 32,273	$ 36,026	$ 36,757
Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amount of Interest Expense presented in the consolidated statements of operations	32,273	36,026	36,757
Interest Rate Swap | Amounts of previously recorded gain/(loss) reclassified from OCI into Interest Expense
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amount of Interest Expense presented in the consolidated statements of operations	(8,286)	(7,751)	4,328
Interest Rate Swap | Amounts of gain (loss) recognized in OCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amount of Interest Expense presented in the consolidated statements of operations	$ 3,786	$ (20,380)	$ (15,119)

Stockholders' Equity (Details)

Stockholders' Equity (Details)	6 Months Ended	12 Months Ended
	Jun. 04, 2020USD ($)	Dec. 31, 2021USD ($)itemshares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares
Stockholders' Equity
Common Stock, Shares, Outstanding		103,998,520	107,328,199
General and Administrative Expense [Member]
Equity-Based Compensation
Compensation cost | $	$ 337,000
2002 Stock Incentive Plan
Equity-Based Compensation
Maximum number of shares provided for grant under equity-based incentive compensation plan		2,000,000
Number of vesting requirements | item		0
Number of shares available for grant under the plan, Beginning		1,847,384	1,906,382	1,944,428
Shares Granted		(66,564)	(58,998)	(38,046)
Number of shares available for grant under the plan, Ending		1,780,820	1,847,384	1,906,382
Compensation Cost, Beginning | $		$ 675,000	$ 337,500
Compensation cost | $		337,500	337,500	$ 337,500
Compensation Cost, Ending | $		$ 1,012,500	$ 675,000	$ 337,500

Stockholders' Equity - Repurcha

Stockholders' Equity - Repurchase of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Jun. 23, 2021
Stockholders' Equity
Shares authorized to be repurchased			$ 50,000
Average cost per share of repurchased shares (in dollars per share)	$ 5.37
Total number of shares repurchased, beginning (in shares)		1,017,498
Shares repurchased (in shares)	3,396,243	3,396,243
Total number of shares repurchased, ending (in shares)	4,413,741	4,413,741
Amount of stock repurchased, beginning		$ 18,775
Aggregate cost of shares repurchased	$ 18,200	18,244
Amount of stock repurchased, ending	$ 37,019	$ 37,019

Federal Income Tax Reporting (D

Federal Income Tax Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Federal Income Tax Reporting
Maximum ownership as a percentage of the voting power or value of the securities of each issuer other than REIT or "TRS"	10.00%
Maximum ownership of securities in all TRS (as a percent)	20.00%			25.00%
Maximum ownership of securities in all TRS when considered together with other non-real estate assets (as a percent)	25.00%
Gross amount of NOL of TRS	$ 4,800	$ 4,600
Period of statute of limitations applicable to the entity's income tax returns	3 years
Net operating losses
NOLs expiration period	20 years
NOLs expired in the period	$ 100
NOLs expected to be used in the next fiscal period	11,800
Reversal of valuation allowance	11,800
Gross amount of NOLs available to company	1,100	13,000
Income Tax Expense
Revised Texas Franchise Tax	234	250	$ 394
Other Taxes	404		(125)
Tax expense	638	250	$ 269
Deferred income taxes	0
Real estate assets net tax basis more (less) than book basis	$ 153,700	$ 253,000

Federal Income Tax Reporting -

Federal Income Tax Reporting - Tax Components of Distributions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tax components of the Company's common distributions paid per share
Ordinary income (in dollars per share)		$ 0.28	$ 0.25
Capital gain (in dollars per share)	$ 0.68	0.06
Return of capital (in dollars per share)		0.02	0.11
Total (in dollars per share)	$ 0.68	$ 0.36	$ 0.36
Ordinary income (as a percent)		77.51%	69.96%
Capital gain (as a percent)	100.00%	16.72%
Return of capital (as a percent)		5.77%	30.04%
Total (as a percent)	100.00%	100.00%	100.00%
Common Stock Dividends Per Share Cash Paid Qualified Distribution		$ 0.009
Qualified distribution as a percentage of total distribution		2.52%

Leases - Lease Costs and Maturi

Leases - Lease Costs and Maturity Analysis for Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)Option	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Leases
Right-of-use asset	$ 1,100
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Prepaid Expense and Other Assets
Option to extend the terms	true
Number of options to extend | Option	1
Extension term	5 years
Lease Costs
Operating lease cost	$ 419	$ 419	$ 419
Lease cost	419	419	419
Cash paid for amounts included in the measurement of lease liabilities	$ 429	$ 421	$ 412
Weighted average remaining lease terms in years - operating leases	2 years 9 months	3 years 9 months	4 years 9 months
Weighted average discount rate - operating leases	3.86%	3.86%	3.86%
Maturity analysis for liabilities
Discount rate at commencement	3.86%
2022	$ 438
2023	447
2024	340
Total undiscounted cash flows	1,225
Present value lease liability	1,159	$ 1,536
Difference between undiscounted cash flows and discounted cash flows	$ 66

Leases - Income Relating to Lea

Leases - Income Relating to Lease Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income relating to lease payments:
Income from leases	$ 203,530	$ 242,209	$ 256,250
Undiscounted Cash Flows
2022	100,269
2023	103,107
2024	97,792
2025	83,596
2026	70,718
2027 and thereafter	259,673
Income relating to lease payments	715,155
Variable lease payments	$ 54,825	$ 61,310	$ 64,421

Retirement Plan (Details)

Retirement Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retirement Plan
Maximum employee compensation to be deferred per year	$ 17,000
Maximum employer matching contribution as a percentage of annual compensation	3.00%
Maximum employee salary that the employer will match	$ 200,000
Company's total contribution under 401 (k) plan	$ 100,000	$ 100,000	$ 200,000

Dispositions of Property (Detai

Dispositions of Property (Details) $ in Thousands	Nov. 16, 2021USD ($)property	Oct. 22, 2021USD ($)	Sep. 23, 2021USD ($)property	Aug. 31, 2021USD ($)	Jun. 29, 2021USD ($)	May 27, 2021USD ($)property	Dec. 23, 2020USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Dispositions of properties
Gain (loss) on sale of property								$ 113,134	$ 41,928
Office Properties in Atlanta, Georgia
Dispositions of properties
Number of properties sold | property						3
Gain (loss) on sale of property		$ 86,800				$ 22,800
Sale price		$ 223,900				$ 219,500
Office Property in Dulles, Virginia
Dispositions of properties
Gain (loss) on sale of property					$ (2,100)
Sale price					$ 17,300
Office property in Indianapolis, Indiana
Dispositions of properties
Gain (loss) on sale of property				$ (1,700)
Sale price				$ 35,000
Office properties in Chesterfield, MO
Dispositions of properties
Number of properties sold | property			2
Gain (loss) on sale of property			$ 10,300
Sale price			$ 67,000
Office property in Chantilly, VA
Dispositions of properties
Number of properties sold | property	2
Gain (loss) on sale of property	$ (2,900)
Sale price	$ 40,000
Office Property In Durham North California
Dispositions of properties
Gain (loss) on sale of property							$ 41,900
Sale price							$ 89,700
Disposal group disposed of by sale, not classified as discontinued operations
Operating results for discontinued operations:
Rental revenue								38,958	72,967	$ 74,626
Rental operating expenses								(11,518)	(20,651)	(22,867)
Real estate taxes and insurance								(5,654)	(11,165)	(10,851)
Depreciation and amortization								(11,929)	(26,552)	(26,927)
Net income (loss) from discontinued operations								$ 9,857	$ 14,599	$ 13,981

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 14, 2022	Jan. 12, 2022	Feb. 10, 2022	Jan. 10, 2022	Dec. 31, 2021
Subsequent Events
Total available					$ 600
Subsequent event
Subsequent Events
Special dividend (in dollars per share)		$ 0.32
BofA Revolver
Subsequent Events
Total available					$ 600
BofA Revolver | Subsequent event
Subsequent Events
Total available			$ 237.5	$ 217.5
Maximum borrowing capacity allowed by exercising an accordion feature				$ 750
Increase in maximum borrowing capacity after exercising accordion feature			$ 20
Cash distribution declared | Subsequent event
Subsequent Events
Cash dividend declared per share (in dollars per share)	$ 0.09

Schedule II Valuation and qua_2

Schedule II Valuation and qualifying accounts (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Allowance for doubtful accounts - Tenant rent receivables
Movement in valuation and qualifying accounts
Balance at beginning of year	$ 505,000	$ 300,000	$ 200,000
Additions (Decreases) charged to costs and expenses	157,000	340,000	213,000
Deductions	(129,000)	(135,000)	(113,000)
Balance at end of year	$ 533,000	505,000	300,000
Allowance for doubtful accounts - Straight-line rent receivable
Movement in valuation and qualifying accounts
Balance at beginning of year		50,000	50,000
Deductions		$ (50,000)
Balance at end of year			$ 50,000

SCHEDULE III REAL ESTATE AND _2

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REAL ESTATE AND ACCUMULATED DEPRECIATION
Encumbrances	$ 0
Accumulated Depreciation	424,487,000	$ 538,717,000	$ 490,697,000	$ 432,579,000
Aggregate cost for Federal Income Tax purposes	1,773,262
Real Estate Excluding Assets Held For Sale
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	147,342,000
Initial cost of Buildings Improvements and Equipment	1,134,057,000
Costs Capitalized (Disposals) Subsequent to Acquisition	334,058,000
Historical Cost of Land	146,848,000
Historical Cost of Buildings Improvements and Equipment	1,468,609,000
Total	1,615,457,000
Accumulated Depreciation	424,487,000
Total Costs, Net of Accumulated Depreciation	1,190,970,000
Forest Park, Charlotte, NC
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	1,559,000
Initial cost of Buildings Improvements and Equipment	5,672,000
Costs Capitalized (Disposals) Subsequent to Acquisition	3,051,000
Historical Cost of Land	1,559,000
Historical Cost of Buildings Improvements and Equipment	8,723,000
Total	10,282,000
Accumulated Depreciation	2,576,000
Total Costs, Net of Accumulated Depreciation	$ 7,706,000
Forest Park, Charlotte, NC | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Forest Park, Charlotte, NC | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Northwest Point, Elk Grove Village, IL
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 2,914,000
Initial cost of Buildings Improvements and Equipment	26,295,000
Costs Capitalized (Disposals) Subsequent to Acquisition	13,023,000
Historical Cost of Land	2,914,000
Historical Cost of Buildings Improvements and Equipment	39,318,000
Total	42,232,000
Accumulated Depreciation	20,586,000
Total Costs, Net of Accumulated Depreciation	$ 21,646,000
Northwest Point, Elk Grove Village, IL | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Northwest Point, Elk Grove Village, IL | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Park Ten, Houston, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 1,061,000
Initial cost of Buildings Improvements and Equipment	21,303,000
Costs Capitalized (Disposals) Subsequent to Acquisition	7,082,000
Historical Cost of Land	567,000
Historical Cost of Buildings Improvements and Equipment	28,879,000
Total	29,446,000
Accumulated Depreciation	14,214,000
Total Costs, Net of Accumulated Depreciation	$ 15,232,000
Park Ten, Houston, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Park Ten, Houston, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Addison, Addison, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 4,325,000
Initial cost of Buildings Improvements and Equipment	48,040,000
Costs Capitalized (Disposals) Subsequent to Acquisition	12,495,000
Historical Cost of Land	4,325,000
Historical Cost of Buildings Improvements and Equipment	60,535,000
Total	64,860,000
Accumulated Depreciation	25,772,000
Total Costs, Net of Accumulated Depreciation	$ 39,088,000
Addison, Addison, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Addison, Addison, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Collins, Richardson, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 4,000,000
Initial cost of Buildings Improvements and Equipment	42,598,000
Costs Capitalized (Disposals) Subsequent to Acquisition	8,804,000
Historical Cost of Land	4,000,000
Historical Cost of Buildings Improvements and Equipment	51,402,000
Total	55,402,000
Accumulated Depreciation	24,755,000
Total Costs, Net of Accumulated Depreciation	$ 30,647,000
Collins, Richardson, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Collins, Richardson, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Greenwood, Englewood, CO
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 3,100,000
Initial cost of Buildings Improvements and Equipment	30,201,000
Costs Capitalized (Disposals) Subsequent to Acquisition	12,530,000
Historical Cost of Land	3,100,000
Historical Cost of Buildings Improvements and Equipment	42,731,000
Total	45,831,000
Accumulated Depreciation	20,295,000
Total Costs, Net of Accumulated Depreciation	$ 25,536,000
Greenwood, Englewood, CO | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Greenwood, Englewood, CO | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Innsbrook, Glenn Allen, VA
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 5,000,000
Initial cost of Buildings Improvements and Equipment	40,216,000
Costs Capitalized (Disposals) Subsequent to Acquisition	9,002,000
Historical Cost of Land	5,000,000
Historical Cost of Buildings Improvements and Equipment	49,218,000
Total	54,218,000
Accumulated Depreciation	20,578,000
Total Costs, Net of Accumulated Depreciation	$ 33,640,000
Innsbrook, Glenn Allen, VA | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Innsbrook, Glenn Allen, VA | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
380 Interlocken, Bloomfield, CO
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 8,275,000
Initial cost of Buildings Improvements and Equipment	34,462,000
Costs Capitalized (Disposals) Subsequent to Acquisition	13,194,000
Historical Cost of Land	8,275,000
Historical Cost of Buildings Improvements and Equipment	47,656,000
Total	55,931,000
Accumulated Depreciation	19,130,000
Total Costs, Net of Accumulated Depreciation	$ 36,801,000
380 Interlocken, Bloomfield, CO | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
380 Interlocken, Bloomfield, CO | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Blue Lagoon, Miami, FL
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 6,306,000
Initial cost of Buildings Improvements and Equipment	46,124,000
Costs Capitalized (Disposals) Subsequent to Acquisition	33,388,000
Historical Cost of Land	6,306,000
Historical Cost of Buildings Improvements and Equipment	79,512,000
Total	85,818,000
Accumulated Depreciation	16,927,000
Total Costs, Net of Accumulated Depreciation	$ 68,891,000
Blue Lagoon, Miami, FL | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Blue Lagoon, Miami, FL | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Eldridge Green, Houston, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 3,900,000
Initial cost of Buildings Improvements and Equipment	43,791,000
Costs Capitalized (Disposals) Subsequent to Acquisition	5,923,000
Historical Cost of Land	3,900,000
Historical Cost of Buildings Improvements and Equipment	49,714,000
Total	53,614,000
Accumulated Depreciation	21,202,000
Total Costs, Net of Accumulated Depreciation	$ 32,412,000
Eldridge Green, Houston, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Eldridge Green, Houston, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Liberty Plaza, Addison, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 4,374,000
Initial cost of Buildings Improvements and Equipment	21,146,000
Costs Capitalized (Disposals) Subsequent to Acquisition	10,542,000
Historical Cost of Land	4,374,000
Historical Cost of Buildings Improvements and Equipment	31,688,000
Total	36,062,000
Accumulated Depreciation	13,172,000
Total Costs, Net of Accumulated Depreciation	$ 22,890,000
Liberty Plaza, Addison, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Liberty Plaza, Addison, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
FSP 390 Interlocken, Broomfield, CO
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 7,013,000
Initial cost of Buildings Improvements and Equipment	37,751,000
Costs Capitalized (Disposals) Subsequent to Acquisition	14,399,000
Historical Cost of Land	7,013,000
Historical Cost of Buildings Improvements and Equipment	52,150,000
Total	59,163,000
Accumulated Depreciation	20,579,000
Total Costs, Net of Accumulated Depreciation	$ 38,584,000
FSP 390 Interlocken, Broomfield, CO | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
FSP 390 Interlocken, Broomfield, CO | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Park Ten II, Houston, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 1,300,000
Initial cost of Buildings Improvements and Equipment	31,712,000
Costs Capitalized (Disposals) Subsequent to Acquisition	7,245,000
Historical Cost of Land	1,300,000
Historical Cost of Buildings Improvements and Equipment	38,957,000
Total	40,257,000
Accumulated Depreciation	13,458,000
Total Costs, Net of Accumulated Depreciation	$ 26,799,000
Park Ten II, Houston, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Park Ten II, Houston, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
121 South Eight Street, Minneapolis, MN
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 4,444,000
Initial cost of Buildings Improvements and Equipment	15,214,000
Costs Capitalized (Disposals) Subsequent to Acquisition	28,449,000
Historical Cost of Land	4,444,000
Historical Cost of Buildings Improvements and Equipment	43,663,000
Total	48,107,000
Accumulated Depreciation	12,968,000
Total Costs, Net of Accumulated Depreciation	$ 35,139,000
121 South Eight Street, Minneapolis, MN | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
121 South Eight Street, Minneapolis, MN | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
801 Marquette Avenue South, Minneapolis, MN
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 4,184,000
Costs Capitalized (Disposals) Subsequent to Acquisition	27,798,000
Historical Cost of Land	4,184,000
Historical Cost of Buildings Improvements and Equipment	27,798,000
Total	31,982,000
Accumulated Depreciation	2,889,000
Total Costs, Net of Accumulated Depreciation	$ 29,093,000
801 Marquette Avenue South, Minneapolis, MN | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
801 Marquette Avenue South, Minneapolis, MN | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
909 Davis, Evanston, IL
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 4,912,000
Initial cost of Buildings Improvements and Equipment	18,229,000
Costs Capitalized (Disposals) Subsequent to Acquisition	8,235,000
Historical Cost of Land	4,912,000
Historical Cost of Buildings Improvements and Equipment	26,464,000
Total	31,376,000
Accumulated Depreciation	8,145,000
Total Costs, Net of Accumulated Depreciation	$ 23,231,000
909 Davis, Evanston, IL | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
909 Davis, Evanston, IL | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Legacy Tennyson Center, Plano, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 3,067,000
Initial cost of Buildings Improvements and Equipment	22,064,000
Costs Capitalized (Disposals) Subsequent to Acquisition	4,046,000
Historical Cost of Land	3,067,000
Historical Cost of Buildings Improvements and Equipment	26,110,000
Total	29,177,000
Accumulated Depreciation	7,756,000
Total Costs, Net of Accumulated Depreciation	$ 21,421,000
Legacy Tennyson Center, Plano, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Legacy Tennyson Center, Plano, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
One Legacy Circle, Plano, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 2,590,000
Initial cost of Buildings Improvements and Equipment	36,608,000
Costs Capitalized (Disposals) Subsequent to Acquisition	4,822,000
Historical Cost of Land	2,590,000
Historical Cost of Buildings Improvements and Equipment	41,430,000
Total	44,020,000
Accumulated Depreciation	11,945,000
Total Costs, Net of Accumulated Depreciation	$ 32,075,000
One Legacy Circle, Plano, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
One Legacy Circle, Plano, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Westchase I & II, Houston, TX
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 8,491,000
Initial cost of Buildings Improvements and Equipment	121,508,000
Costs Capitalized (Disposals) Subsequent to Acquisition	17,044,000
Historical Cost of Land	8,491,000
Historical Cost of Buildings Improvements and Equipment	138,552,000
Total	147,043,000
Accumulated Depreciation	33,721,000
Total Costs, Net of Accumulated Depreciation	$ 113,322,000
Westchase I & II, Houston, TX | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Westchase I & II, Houston, TX | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
1999 Broadway, CO
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 16,334,000
Initial cost of Buildings Improvements and Equipment	137,726,000
Costs Capitalized (Disposals) Subsequent to Acquisition	39,108,000
Historical Cost of Land	16,334,000
Historical Cost of Buildings Improvements and Equipment	176,834,000
Total	193,168,000
Accumulated Depreciation	40,105,000
Total Costs, Net of Accumulated Depreciation	$ 153,063,000
1999 Broadway, CO | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
1999 Broadway, CO | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
1001 17th Street, CO
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 17,413,000
Initial cost of Buildings Improvements and Equipment	165,058,000
Costs Capitalized (Disposals) Subsequent to Acquisition	24,286,000
Historical Cost of Land	17,413,000
Historical Cost of Buildings Improvements and Equipment	189,344,000
Total	206,757,000
Accumulated Depreciation	41,367,000
Total Costs, Net of Accumulated Depreciation	$ 165,390,000
1001 17th Street, CO | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
1001 17th Street, CO | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Plaza Seven, Minneapolis, MN
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 6,604,000
Initial cost of Buildings Improvements and Equipment	54,240,000
Costs Capitalized (Disposals) Subsequent to Acquisition	11,468,000
Historical Cost of Land	6,604,000
Historical Cost of Buildings Improvements and Equipment	65,708,000
Total	72,312,000
Accumulated Depreciation	11,471,000
Total Costs, Net of Accumulated Depreciation	$ 60,841,000
Plaza Seven, Minneapolis, MN | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Plaza Seven, Minneapolis, MN | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
Pershing Plaza, Atlanta, GA
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 5,300,000
Initial cost of Buildings Improvements and Equipment	34,158,000
Costs Capitalized (Disposals) Subsequent to Acquisition	4,119,000
Historical Cost of Land	5,300,000
Historical Cost of Buildings Improvements and Equipment	38,277,000
Total	43,577,000
Accumulated Depreciation	5,147,000
Total Costs, Net of Accumulated Depreciation	$ 38,430,000
Pershing Plaza, Atlanta, GA | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
Pershing Plaza, Atlanta, GA | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years
600 17th Street, Denver, Co
REAL ESTATE AND ACCUMULATED DEPRECIATION
Initial cost of Land	$ 20,876,000
Initial cost of Buildings Improvements and Equipment	99,941,000
Costs Capitalized (Disposals) Subsequent to Acquisition	14,005,000
Historical Cost of Land	20,876,000
Historical Cost of Buildings Improvements and Equipment	113,946,000
Total	134,822,000
Accumulated Depreciation	15,729,000
Total Costs, Net of Accumulated Depreciation	$ 119,093,000
600 17th Street, Denver, Co | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	5 years
600 17th Street, Denver, Co | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Depreciable Life Years	39 years

SCHEDULE III REAL ESTATE AND _3

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION - Changes in real estate investments and accumulated depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Real estate investments, at cost:
Balance, beginning of year	$ 2,140,733	$ 2,127,907	$ 2,058,352
Improvements	60,910	75,472	74,324
Dispositions	(586,186)	(62,646)	(4,769)
Balance, end of year	1,615,457	2,140,733	2,127,907
Accumulated depreciation:
Balance, beginning of year	538,717	490,697	432,579
Depreciation	60,080	67,001	62,887
Dispositions	(174,310)	(18,981)	(4,769)
Balance, end of year	$ 424,487	$ 538,717	$ 490,697