STAG Industrial (STAG) 10-Q 4 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 03, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	1-34907
Entity Registrant Name	STAG Industrial, Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	27-3099608
Entity Address, Address Line One	One Federal Street
Entity Address, Address Line Two	23rd Floor
Entity Address, City or Town	Boston,
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	617
Local Phone Number	574-4777
Title of 12(b) Security	Common stock, $0.01 par value per share
Trading Symbol	STAG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001479094
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		159,688,186
Entity Central Index Key	0001479094
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Rental Property:
Land	$ 500,947	$ 492,783
Buildings and improvements, net of accumulated depreciation of $524,965 and $495,348, respectively	3,565,366	3,532,608
Deferred leasing intangibles, net of accumulated amortization of $264,103 and $258,005, respectively	490,532	499,802
Total rental property, net	4,556,845	4,525,193
Cash and cash equivalents	18,579	15,666
Restricted cash	3,738	4,673
Tenant accounts receivable	79,956	77,796
Prepaid expenses and other assets	44,841	43,471
Interest rate swaps	3,592	0
Operating lease right-of-use assets	25,016	25,403
Assets held for sale, net	0	444
Total assets	4,732,567	4,692,646
Liabilities:
Unsecured credit facility	233,000	107,000
Unsecured term loans, net	970,572	971,111
Unsecured notes, net	573,377	573,281
Mortgage notes, net	56,341	51,898
Accounts payable, accrued expenses and other liabilities	60,600	69,765
Interest rate swaps	32,106	40,656
Tenant prepaid rent and security deposits	27,522	27,844
Dividends and distributions payable	19,657	19,379
Deferred leasing intangibles, net of accumulated amortization of $16,105 and $15,759, respectively	33,559	32,762
Operating lease liabilities	27,717	27,898
Total liabilities	2,034,451	1,921,594
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock	0	75,000
Common stock, par value $0.01 per share, 300,000,000 shares authorized at March 31, 2021 and December 31, 2020, respectively, 159,082,448 and 158,209,823 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively	1,591	1,582
Additional paid-in capital	3,443,787	3,421,721
Cumulative dividends in excess of earnings	(778,727)	(742,071)
Accumulated other comprehensive loss	(28,143)	(40,025)
Stockholders' Equity Attributable to Parent, Total	2,638,508	2,716,207
Noncontrolling interest	59,608	54,845
Total equity	2,698,116	2,771,052
Total liabilities and equity	$ 4,732,567	$ 4,692,646

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Building and Improvements, accumulated depreciation	$ 524,965	$ 495,348
Deferred leasing intangible assets, accumulated amortization	264,103	258,005
Deferred leasing intangible liabilities, accumulated amortization	$ 16,105	$ 15,759
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Shares Issued	0
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	300,000,000	300,000,000
Common Stock, Shares, Issued	159,082,448	158,209,823
Common Stock, Shares, Outstanding	159,082,448	158,209,823
Series C Preferred Stock
Preferred Stock, Shares Issued	0	3,000,000
Preferred Stock, Shares Outstanding	0	3,000,000
Preferred Stock, Liquidation Preference Per Share		$ 25

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues [Abstract]
Rental income	$ 133,825	$ 118,339
Other income	170	209
Total revenue	133,995	118,548
Expenses
Property	27,002	21,947
General and administrative	12,790	10,373
Depreciation and amortization	58,407	52,688
Other expenses	852	476
Total expenses	99,051	85,484
Other income (expense)
Interest and other income	32	79
Interest expense	(15,358)	(14,864)
Debt extinguishment and modification expenses	(679)	0
Gain on the sales of rental property, net	6,409	46,759
Total other income (expense)	(9,596)	31,974
Net income	25,348	65,038
Less: income attributable to noncontrolling interest after preferred stock dividends	473	1,598
Net income attributable to STAG Industrial, Inc.	24,875	63,440
Less: preferred stock dividends	1,289	1,289
Less: redemption of preferred stock	2,582	0
Less: amount allocated to participating securities	73	79
Net income attributable to common stockholders	$ 20,931	$ 62,072
Weighted average common shares outstanding — basic	158,430	147,570
Weighted average common shares outstanding — diluted	159,126	147,656
Net income per share — basic and diluted
Net income per share attributable to common stockholders — basic	$ 0.13	$ 0.42
Net income per share attributable to common stockholders — diluted	$ 0.13	$ 0.42

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 25,348	$ 65,038
Other comprehensive income (loss):
Income (loss) on interest rate swaps	12,150	(30,191)
Other comprehensive income (loss)	12,150	(30,191)
Comprehensive income	37,498	34,847
Income attributable to noncontrolling interest after preferred stock dividends	(473)	(1,598)
Other comprehensive (income) loss attributable to noncontrolling interest	(268)	757
Comprehensive income attributable to STAG Industrial, Inc.	$ 36,757	$ 34,006

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Cumulative Dividends in excess of Earnings	Accumulated Other Comprehensive Income (Loss)	Total Stockholders' Equity	Noncontrolling Interest - Unit holders in Operating Partnership
Balance at Dec. 31, 2019	$ 2,363,891	$ 75,000	$ 1,428	$ 2,970,553	$ (723,027)	$ (18,426)	$ 2,305,528	$ 58,363
Balance (in shares) at Dec. 31, 2019			142,815,593
Increase (Decrease) in Stockholders' Equity
Proceeds from sales of common stock, net	172,723		$ 56	172,667			172,723
Proceeds from sales of common stock (in shares)			5,600,000
Dividends, Common Stock					(54,822)
Dividends							(54,822)
Distribution Made to Limited Partner, Cash Distributions Declared								(896)
Dividends and Distributions, Net	(55,718)
Non-cash compensation activity, net	1,371			(858)			(1,247)	2,618
Non-cash compensation activity (in shares)			73,048
Non-cash compensation activity (in excess of earnings)			$ (1)		(390)
Redemption of common units to common stock			$ (2)	(3,426)			(3,428)	(3,428)
Redemption of common units to common stock (in shares)			219,390
Rebalancing of noncontrolling interest				(3,293)			(3,293)	3,293
Other comprehensive income	(30,191)					(29,434)	(29,434)	(757)
Net income	65,038				63,440		63,440	1,598
Balance at Mar. 31, 2020	2,517,114	75,000	$ 1,487	3,142,495	(714,799)	(47,860)	2,456,323	60,791
Balance (in shares) at Mar. 31, 2020			148,708,031
Balance at Dec. 31, 2019	2,363,891	75,000	$ 1,428	2,970,553	(723,027)	(18,426)	2,305,528	$ 58,363
Balance (in shares) at Dec. 31, 2019			142,815,593
Increase (Decrease) in Stockholders' Equity
Redemption of common units to common stock (in shares)								0
Balance at Dec. 31, 2020	2,771,052	75,000	$ 1,582	3,421,721	(742,071)	(40,025)	2,716,207	$ 54,845
Balance (in shares) at Dec. 31, 2020			158,209,823
Increase (Decrease) in Stockholders' Equity
Proceeds from sales of common stock, net	21,566		$ 7	21,559			21,566
Proceeds from sales of common stock (in shares)			680,276
Redemption of preferred stock	(75,009)	(75,000)		(2,573)	(2,582)		(75,009)
Dividends, Common Stock					(58,828)
Dividends							(58,828)
Distribution Made to Limited Partner, Cash Distributions Declared								(1,436)
Dividends and Distributions, Net	(60,264)
Non-cash compensation activity, net	3,273			(3,214)			(3,334)	6,607
Non-cash compensation activity (in shares)			95,190
Non-cash compensation activity (in excess of earnings)			$ (1)		(121)
Redemption of common units to common stock			$ (1)	(1,622)			(1,623)	$ (1,623)
Redemption of common units to common stock (in shares)			97,159					0
Rebalancing of noncontrolling interest				(474)			(474)	$ 474
Other comprehensive income	12,150					11,882	11,882	268
Net income	25,348				24,875		24,875	473
Balance at Mar. 31, 2021	$ 2,698,116	$ 0	$ 1,591	$ 3,443,787	$ (778,727)	$ (28,143)	$ 2,638,508	$ 59,608
Balance (in shares) at Mar. 31, 2021			159,082,448

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income	$ 25,348	$ 65,038
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	58,407	52,688
Non-cash portion of interest expense	487	676
Amortization of above and below market leases, net	1,474	984
Straight-line rent adjustments, net	(4,676)	(3,849)
Gain on the sales of rental property, net	(6,409)	(46,759)
Non-cash compensation expense	4,615	2,852
Change in assets and liabilities:
Tenant accounts receivable	3,281	(509)
Prepaid expenses and other assets	(4,132)	(490)
Accounts payable, accrued expenses and other liabilities	(4,613)	390
Tenant prepaid rent and security deposits	(322)	(441)
Total adjustments	48,112	5,542
Net cash provided by operating activities	73,460	70,580
Cash flows from investing activities:
Acquisitions of land and buildings and improvements	(81,969)	(100,187)
Additions of land and building and improvements	(10,269)	(16,815)
Acquisitions of other assets	0	450
Proceeds from sales of rental property, net	23,884	99,678
Acquisition deposits, net	2,008	500
Acquisitions of deferred leasing intangibles	(13,156)	(18,706)
Net cash used in investing activities	(79,502)	(35,980)
Cash flows from financing activities:
Proceeds from unsecured credit facility	393,000	387,000
Repayment of unsecured credit facility	(267,000)	(308,000)
Proceeds from unsecured term loans	300,000	100,000
Repayment of unsecured term loans	(300,000)	0
Repayment of mortgage notes	(531)	(497)
Payment of loan fees and costs	2,750	0
Proceeds from sales of common stock, net	21,639	172,771
Redemption of preferred stock	(75,000)	0
Dividends and distributions	59,996	54,883
Repurchase and retirement of share-based compensation	(1,342)	(1,472)
Net cash provided by financing activities	8,020	294,919
Increase in cash and cash equivalents and restricted cash	1,978	329,519
Cash and cash equivalents and restricted cash—beginning of period	20,339	11,864
Cash and cash equivalents and restricted cash—end of period	22,317	341,383
Supplemental disclosure:
Cash paid for interest, net of capitalized interest	13,471	12,544
Supplemental schedule of non-cash investing and financing activities
Acquisitions of land and buildings and improvements	4,239	0
Acquisitions of deferred leasing intangibles	703	0
Change in additions of land, building, and improvements included in accounts payable, accrued expenses, and other liabilities	4,281	(1,080)
Additions to building and other capital improvements from non-cash compensation	0	(8)
Assumption of mortgage notes	5,103	0
Fair market value adjustment to mortgage notes acquired	(161)	0
Change in loan fees, costs, and offering costs included in accounts payable, accrued expenses, and other liabilities	879	(62)
Dividends and distributions payable	$ 19,657	$ 18,301

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business STAG Industrial, Inc. (the “Company”) is an industrial real estate operating company focused on the acquisition and operation of single-tenant, industrial properties throughout the United States. The Company was formed as a Maryland corporation and has elected to be treated and intends to continue to qualify as a real estate investment trust (“REIT”) under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended. The Company is structured as an umbrella partnership REIT, commonly called an UPREIT, and owns substantially all of its assets and conducts substantially all of its business through its operating partnership, STAG Industrial Operating Partnership, L.P., a Delaware limited partnership (the “Operating Partnership”). As of March 31, 2021 and December 31, 2020, the Company owned a 97.8% and 98.0%, respectively, common equity interest in the Operating Partnership. The Company, through its wholly owned subsidiary, is the sole general partner of the Operating Partnership. As used herein, the “Company” refers to STAG Industrial, Inc. and its consolidated subsidiaries and partnerships, including the Operating Partnership, except where context otherwise requires. As of March 31, 2021, the Company owned 494 buildings in 39 states with approximately 99.1 million rentable square feet, consisting of 414 warehouse/distribution buildings, 72 light manufacturing buildings, and eight flex/office buildings. COVID-19 Pandemic Currently, one of the most significant risks and uncertainties facing the Company and the real estate industry generally is the potential adverse effect of the ongoing public health crisis of the novel coronavirus disease (“COVID-19”) pandemic. The Company closely monitors the effect of the COVID-19 pandemic on all aspects of its business, including how the pandemic will affect its tenants and business partners. The Company did not incur significant disruptions from the COVID-19 pandemic during the three months ended March 31, 2021. In addition, the Company did not enter into any rent deferral agreements during the three months ended March 31, 2021. The Company will continue to evaluate tenant rent relief requests on an individual basis, considering a number of factors. Not all tenant requests will ultimately result in modified agreements, nor is the Company foregoing its contractual rights under its lease agreements. The Company remains unable to predict the ultimate impact that the pandemic will have on its financial condition, results of operations and cash flows due to numerous uncertainties. The extent to which the COVID-19 pandemic affects the Company’s operations and those of its tenants will depend on future developments, which are highly uncertain and cannot be predicted with confidence, including the scope, severity and duration of the pandemic, the actions taken to contain the pandemic or mitigate its impact, and the direct and indirect economic effects of the pandemic and containment measures, among others.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Interim Financial Information The accompanying interim financial statements have been presented in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and with the instructions to Form 10-Q and Regulation S-X for interim financial information. Accordingly, these statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the accompanying interim financial statements include all adjustments, consisting of normal recurring items, necessary for their fair statement in conformity with GAAP. Interim results are not necessarily indicative of results for a full year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020. Basis of Presentation The Company’s consolidated financial statements include the accounts of the Company, the Operating Partnership, and their subsidiaries. Interests in the Operating Partnership not owned by the Company are referred to as “Noncontrolling Common Units.” These Noncontrolling Common Units are held by other limited partners in the form of common units (“Other Common Units”) and long term incentive plan units (“LTIP units”) issued pursuant to the STAG Industrial, Inc. 2011 Equity Incentive Plan, as amended and restated (the “2011 Plan”). All significant intercompany balances and transactions have been eliminated in the consolidation of entities. The financial statements of the Company are presented on a consolidated basis for all periods presented. Restricted Cash The following table presents a reconciliation of cash and cash equivalents and restricted cash reported on the accompanying Consolidated Balance Sheets to amounts reported on the accompanying Consolidated Statements of Cash Flows. Reconciliation of cash and cash equivalents and restricted cash (in thousands) March 31, 2021 December 31, 2020 Cash and cash equivalents $ 18,579 $ 15,666 Restricted cash 3,738 4,673 Total cash and cash equivalents and restricted cash $ 22,317 $ 20,339 Incentive and Equity-Based Employee Compensation Plans On January 7, 2021, the Company adopted the STAG Industrial, Inc. Employee Retirement Vesting Program (the “Vesting Program”) to provide supplemental retirement benefits for eligible employees. For those employees who are retirement eligible or will become retirement eligible during the applicable vesting period under the terms of the Vesting Program, the Company accelerates equity-based compensation through the employee’s six Taxes Federal Income Taxes The Company’s taxable REIT subsidiary did not have any activity during the three months ended March 31, 2021 and 2020. State and Local Income, Excise, and Franchise Tax State and local income, excise, and franchise taxes in the amount of $0.4 million and $0.4 million have been recorded in other expenses on the accompanying Consolidated Statements of Operations for the three months ended March 31, 2021 and 2020, respectively. Uncertain Tax Positions As of March 31, 2021 and December 31, 2020, there were no liabilities for uncertain tax positions. Concentrations of Credit Risk

Rental Property

Rental Property	3 Months Ended
	Mar. 31, 2021
Real Estate [Abstract]
Rental Property	Rental Property The following table summarizes the components of rental property as of March 31, 2021 and December 31, 2020. Rental Property (in thousands) March 31, 2021 December 31, 2020 Land $ 500,947 $ 492,783 Buildings, net of accumulated depreciation of $347,390 and $327,043, respectively 3,242,182 3,195,439 Tenant improvements, net of accumulated depreciation of $25,333 and $24,891, respectively 42,290 43,684 Building and land improvements, net of accumulated depreciation of $152,242 and $143,414, respectively 274,135 275,433 Construction in progress 6,759 18,052 Deferred leasing intangibles, net of accumulated amortization of $264,103 and $258,005, respectively 490,532 499,802 Total rental property, net $ 4,556,845 $ 4,525,193 Acquisitions The following table summarizes the acquisitions of the Company during the three months ended March 31, 2021. The Company accounted for all of its acquisitions as asset acquisitions. Market (1) Date Acquired Square Feet Number of Buildings Purchase Price Omaha/Council Bluffs, NE-IA January 21, 2021 370,000 1 $ 24,922 Minneapolis/St Paul, MN February 24, 2021 80,655 1 10,174 Long Island, NY February 25, 2021 64,224 1 8,516 Sacramento, CA February 25, 2021 267,284 1 25,917 Little Rock/N Little Rock March 1, 2021 300,160 1 24,317 Cleveland, OH March 18, 2021 170,000 1 6,382 Three months ended March 31, 2021 1,252,323 6 $ 100,228 (1) As defined by CoStar Realty Information Inc (“CoStar”). If the building is located outside of a CoStar defined market, the city and state is reflected. The following table summarizes the allocation of the consideration paid at the date of acquisition during the three months ended March 31, 2021 for the acquired assets and liabilities in connection with the acquisitions identified in the table above. Acquired Assets and Liabilities Purchase Price (in thousands) Weighted Average Amortization Period (years) of Intangibles at Acquisition Land $ 9,766 N/A Buildings 71,738 N/A Tenant improvements 757 N/A Building and land improvements 3,947 N/A Deferred leasing intangibles - In-place leases 9,813 8.7 Deferred leasing intangibles - Tenant relationships 4,704 11.5 Deferred leasing intangibles - Above market leases 1,975 15.0 Deferred leasing intangibles - Below market leases (2,633) 5.9 Below market assumed debt adjustment 161 18.8 Total purchase price $ 100,228 Less: Mortgage notes assumed (5,103) Net assets acquired $ 95,125 On February 25, 2021, the Company assumed a mortgage note of approximately $5.1 million in connection with the acquisition of the property located in Long Island, NY. For a discussion of the method used to determine the fair value of the mortgage note, see Note 4. The following table summarizes the results of operations for the three months ended March 31, 2021 for the buildings acquired during the three months ended March 31, 2021 included in the Company’s Consolidated Statements of Operations from the date of acquisition. Results of Operations (in thousands) Three months ended March 31, 2021 Total revenue $ 1,287 Net income $ 23 Dispositions During the three months ended March 31, 2021, the Company sold four buildings to third parties comprised of approximately 0.5 million rentable square feet with a net book value of approximately $17.5 million. These buildings contributed approximately $10,000 and $0.4 million to revenue for the three months ended March 31, 2021 and 2020, respectively. These buildings contributed approximately $0.1 million and $0.1 million to net loss (exclusive of gain on the sales of rental property, net) for the three months ended March 31, 2021 and 2020, respectively. Net proceeds from the sales of rental property were approximately $23.9 million and the Company recognized the full gain on the sales of rental property, net, of approximately $6.4 million for the three months ended March 31, 2021. Deferred Leasing Intangibles The following table summarizes the deferred leasing intangibles on the accompanying Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020. March 31, 2021 December 31, 2020 Deferred Leasing Intangibles (in thousands) Gross Accumulated Amortization Net Gross Accumulated Amortization Net Above market leases $ 92,406 $ (35,251) $ 57,155 $ 92,125 $ (33,629) $ 58,496 Other intangible lease assets 662,229 (228,852) 433,377 665,682 (224,376) 441,306 Total deferred leasing intangible assets $ 754,635 $ (264,103) $ 490,532 $ 757,807 $ (258,005) $ 499,802 Below market leases $ 49,664 $ (16,105) $ 33,559 $ 48,521 $ (15,759) $ 32,762 Total deferred leasing intangible liabilities $ 49,664 $ (16,105) $ 33,559 $ 48,521 $ (15,759) $ 32,762 The following table summarizes the amortization expense and the net decrease to rental income for the amortization of deferred leasing intangibles during the three months ended March 31, 2021 and 2020. Three months ended March 31, Deferred Leasing Intangibles Amortization (in thousands) 2021 2020 Net decrease to rental income related to above and below market lease amortization $ 1,480 $ 990 Amortization expense related to other intangible lease assets $ 22,447 $ 20,302 The following table summarizes the amortization of deferred leasing intangibles over the next five calendar years beginning with 2021 as of March 31, 2021. Year Amortization Expense Related to Other Intangible Lease Assets (in thousands) Net Decrease to Rental Income Related to Above and Below Market Lease Amortization (in thousands) Remainder of 2021 $ 56,927 $ 517 2022 $ 67,300 $ 483 2023 $ 58,725 $ 983 2024 $ 49,665 $ 1,452 2025 $ 42,085 $ 1,283

Debt

Debt	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Debt	DebtThe following table summarizes the Company’s outstanding indebtedness, including borrowings under the Company’s unsecured credit facility, unsecured term loans, unsecured notes, and mortgage notes as of March 31, 2021 and December 31, 2020. Loan Principal Outstanding as of March 31, 2021 (in thousands) Principal Outstanding as of December 31, 2020 (in thousands) Interest Rate (1)(2) Maturity Date Prepayment Terms (3) Unsecured credit facility: Unsecured Credit Facility (4) $ 233,000 $ 107,000 L + 0.90% January 12, 2024 i Total unsecured credit facility 233,000 107,000 Unsecured term loans: Unsecured Term Loan A 150,000 150,000 3.38 % March 31, 2022 i Unsecured Term Loan D 150,000 150,000 2.85 % January 4, 2023 i Unsecured Term Loan E 175,000 175,000 3.92 % January 15, 2024 i Unsecured Term Loan F 200,000 200,000 3.11 % January 12, 2025 i Unsecured Term Loan G 300,000 300,000 1.28 % February 5, 2026 i Total unsecured term loans 975,000 975,000 Total unamortized deferred financing fees and debt issuance costs (4,428) (3,889) Total carrying value unsecured term loans, net 970,572 971,111 Unsecured notes: Series F Unsecured Notes 100,000 100,000 3.98 % January 5, 2023 ii Series A Unsecured Notes 50,000 50,000 4.98 % October 1, 2024 ii Series D Unsecured Notes 100,000 100,000 4.32 % February 20, 2025 ii Series G Unsecured Notes 75,000 75,000 4.10 % June 13, 2025 ii Series B Unsecured Notes 50,000 50,000 4.98 % July 1, 2026 ii Series C Unsecured Notes 80,000 80,000 4.42 % December 30, 2026 ii Series E Unsecured Notes 20,000 20,000 4.42 % February 20, 2027 ii Series H Unsecured Notes 100,000 100,000 4.27 % June 13, 2028 ii Total unsecured notes 575,000 575,000 Total unamortized deferred financing fees and debt issuance costs (1,623) (1,719) Total carrying value unsecured notes, net 573,377 573,281 Mortgage notes (secured debt): Wells Fargo Bank, National Association CMBS Loan 48,063 48,546 4.31 % December 1, 2022 iii Thrivent Financial for Lutherans 3,527 3,556 4.78 % December 15, 2023 iv United of Omaha Life Insurance Company 5,087 — 3.71 % October 1, 2039 ii Total mortgage notes 56,677 52,102 Net unamortized fair market value premium (discount) (134) 29 Total unamortized deferred financing fees and debt issuance costs (202) (233) Total carrying value mortgage notes, net 56,341 51,898 Total / weighted average interest rate (5) $ 1,833,290 $ 1,703,290 3.05 % (1) Interest rate as of March 31, 2021. At March 31, 2021, the one-month LIBOR (“L”) was 0.11113%. The current interest rate is not adjusted to include the amortization of deferred financing fees or debt issuance costs incurred in obtaining debt or any unamortized fair market value premiums. The spread over the applicable rate for the Company’s unsecured credit facility and unsecured term loans is based on the Company’s debt rating, as defined in the respective loan agreements. (2) The unsecured term loans have a stated interest rate of one-month LIBOR plus a spread of 1.0%. As of March 31, 2021, one-month LIBOR for the Unsecured Term Loans A, D, E, F, and G was swapped to a fixed rate of 2.38%, 1.85%, 2.92%, 2.11%, and 0.28%, respectively. One-month LIBOR for the Unsecured Term Loan G will be swapped to a fixed rate of 0.94% effective April 18, 2023. (3) Prepayment terms consist of (i) pre-payable with no penalty; (ii) pre-payable with penalty; (iii) pre-payable without penalty three months prior to the maturity date, however can be defeased; and (iv) pre-payable without penalty three months prior to the maturity date. (4) The capacity of the unsecured credit facility is $750.0 million. Deferred financing fees and debt issuance costs, net of accumulated amortization related to the unsecured credit facility of approximately $2.5 million and $1.6 million is included in prepaid expenses and other assets on the accompanying Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020, respectively. The initial maturity date is January 15, 2023, which may be extended pursuant to two six (5) The weighted average interest rate was calculated using the fixed interest rate swapped on the notional amount of $975.0 million of debt, and is not adjusted to include the amortization of deferred financing fees or debt issuance costs incurred in obtaining debt or any unamortized fair market value premiums or discounts. The aggregate undrawn nominal commitment on the unsecured credit facility as of March 31, 2021 was approximately $514.4 million, including issued letters of credit. The Company’s actual borrowing capacity at any given point in time may be less and is restricted to a maximum amount based on the Company’s debt covenant compliance. Total accrued interest for the Company’s indebtedness was approximately $7.9 million and $6.3 million as of March 31, 2021 and December 31, 2020, respectively, and is included in accounts payable, accrued expenses and other liabilities on the accompanying Consolidated Balance Sheets. The following table summarizes the costs included in interest expense related to the Company’s debt arrangements on the accompanying Consolidated Statement of Operations for the three months ended March 31, 2021 and 2020. Three months ended March 31, Costs Included in Interest Expense (in thousands) 2021 2020 Amortization of deferred financing fees and debt issuance costs and fair market value premiums/discounts $ 487 $ 676 Facility, unused, and other fees $ 386 $ 364 On February 25 2021, the Company assumed a mortgage note with United of Omaha Life Insurance Company of approximately $5.1 million in connection with the acquisition of the property located in Long Island, NY, which serves as collateral for the debt. The debt matures on October 1, 2039 and bears interest at 3.71% per annum. The assumed debt was recorded at fair value and a fair value discount of approximately $0.2 million was recorded during three months ended March 31, 2021. The fair value of debt was determined by discounting the future cash flows using the current rate of approximately 4.10% at which loans would be made to borrowers with similar credit ratings for loans with similar maturities, terms, and loan-to-value ratios. The fair value of the debt is based on Level 3 inputs and is a nonrecurring fair value measurement. On February 5, 2021, the Company entered into an amendment to the unsecured credit facility (the “Credit Facility Amendment”). The Credit Facility Amendment provides for an increase in the aggregate commitments available for borrowing under the unsecured credit facility from $500 million to up to $750 million. As of March 31, 2021, the unsecured credit facility bore an interest rate of LIBOR plus a spread of 0.90% based on the Company’s debt rating, as defined in the loan agreement. In connection with the Credit Facility Amendment, the Company incurred approximately $1.2 million in costs which are being deferred and amortized through the maturity date of the unsecured credit facility. Other than the increase in the borrowing commitments, the material terms of the unsecured credit facility remain unchanged. On February 5, 2021, the Company entered into an amendment to the Unsecured Term Loan G (the “Amendment to Unsecured Term Loan G”). The Amendment to Unsecured Term Loan G provides for an extension of the maturity date to February 5, 2026 and a reduced stated interest rate of one-month LIBOR plus a spread that ranges from 0.85% to 1.65% for LIBOR borrowings based on the Company’s debt ratings. The Amendment to Unsecured Term Loan G also amended the provision for a minimum interest rate, or floor, for LIBOR borrowings to 0.00% and for Base Rate borrowings to 1.00%. As of March 31, 2021 , borrowings under the Unsecured Term Loan G bore interest at LIBOR plus 1.00%. In connection with the Amendment to Unsecured Term Loan G, the Company incurred approximately $1.6 million in costs which are being deferred and amortized through the new maturity date of February 5, 2026. The Company also incurred approximately $0.7 million of modification expenses which were recognized in debt extinguishment and modification expenses in the accompanying Consolidated Statements of Operations. Additionally, the Company reversed the previously accrued extension fees of approximately $1.1 million from the amendment to the Unsecured Term Loan G that was entered into on April 17, 2020, which resulted in a decrease to interest expense of approximately $0.3 million. Other than the maturity and interest rate provisions described above, the material terms of the Unsecured Term Loan G remain unchanged. Financial Covenant Considerations The Company was in compliance with all financial and other covenants as of March 31, 2021 and December 31, 2020 related to its unsecured credit facility, unsecured term loans, unsecured notes, and mortgage notes. The real estate net book value of the properties that are collateral for the Company’s debt arrangements was approximately $89.0 million and $81.4 million at March 31, 2021 and December 31, 2020, respectively, and is limited to senior, property-level secured debt financing arrangements. Fair Value of Debt The following table summarizes the aggregate principal outstanding under the Company’s debt arrangements and the corresponding estimate of fair value as of March 31, 2021 and December 31, 2020. March 31, 2021 December 31, 2020 Indebtedness (in thousands) Principal Outstanding Fair Value Principal Outstanding Fair Value Unsecured credit facility $ 233,000 $ 233,000 $ 107,000 $ 107,000 Unsecured term loans 975,000 975,000 975,000 978,448 Unsecured notes 575,000 628,674 575,000 628,575 Mortgage notes 56,677 58,841 52,102 54,485 Total principal amount 1,839,677 $ 1,895,515 1,709,102 $ 1,768,508 Net unamortized fair market value premium (discount) (134) 29 Total unamortized deferred financing fees and debt issuance costs (6,253) (5,841) Total carrying value $ 1,833,290 $ 1,703,290

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments Risk Management Objective of Using Derivatives The Company’s use of derivative instruments is limited to the utilization of interest rate swaps to manage interest rate risk exposure on existing and future liabilities and not for speculative purposes. The principal objective of such arrangements is to minimize the risks and related costs associated with the Company’s operating and financial structure. The following table summarizes the Company’s outstanding interest rate swaps as of March 31, 2021. All of the Company’s interest rate swaps are designated as qualifying cash flow hedges. Interest Rate Trade Date Effective Date Notional Amount Fair Value Pay Fixed Interest Rate Receive Variable Interest Rate Maturity Date Wells Fargo Bank, N.A. Jan-08-2015 Mar-20-2015 $ 25,000 $ (426) 1.8280 % One-month L Mar-31-2022 The Toronto-Dominion Bank Jan-08-2015 Feb-14-2020 $ 25,000 $ (584) 2.4535 % One-month L Mar-31-2022 Regions Bank Jan-08-2015 Feb-14-2020 $ 50,000 $ (1,178) 2.4750 % One-month L Mar-31-2022 Capital One, N.A. Jan-08-2015 Feb-14-2020 $ 50,000 $ (1,206) 2.5300 % One-month L Mar-31-2022 The Toronto-Dominion Bank Jul-20-2017 Oct-30-2017 $ 25,000 $ (739) 1.8485 % One-month L Jan-04-2023 Royal Bank of Canada Jul-20-2017 Oct-30-2017 $ 25,000 $ (740) 1.8505 % One-month L Jan-04-2023 Wells Fargo Bank, N.A. Jul-20-2017 Oct-30-2017 $ 25,000 $ (740) 1.8505 % One-month L Jan-04-2023 PNC Bank, N.A. Jul-20-2017 Oct-30-2017 $ 25,000 $ (739) 1.8485 % One-month L Jan-04-2023 PNC Bank, N.A. Jul-20-2017 Oct-30-2017 $ 50,000 $ (1,477) 1.8475 % One-month L Jan-04-2023 The Toronto-Dominion Bank Apr-20-2020 Sep-29-2020 $ 75,000 $ (83) 0.2750 % One-month L Apr-18-2023 Wells Fargo Bank, N.A. Apr-20-2020 Sep-29-2020 $ 75,000 $ (90) 0.2790 % One-month L Apr-18-2023 The Toronto-Dominion Bank Apr-20-2020 Mar-19-2021 $ 75,000 $ (83) 0.2750 % One-month L Apr-18-2023 Wells Fargo Bank, N.A. Apr-20-2020 Mar-19-2021 $ 75,000 $ (91) 0.2800 % One-month L Apr-18-2023 The Toronto-Dominion Bank Jul-24-2018 Jul-26-2019 $ 50,000 $ (3,585) 2.9180 % One-month L Jan-12-2024 PNC Bank, N.A. Jul-24-2018 Jul-26-2019 $ 50,000 $ (3,582) 2.9190 % One-month L Jan-12-2024 Bank of Montreal Jul-24-2018 Jul-26-2019 $ 50,000 $ (3,582) 2.9190 % One-month L Jan-12-2024 U.S. Bank, N.A. Jul-24-2018 Jul-26-2019 $ 25,000 $ (1,793) 2.9190 % One-month L Jan-12-2024 Wells Fargo Bank, N.A. May-02-2019 Jul-15-2020 $ 50,000 $ (3,100) 2.2460 % One-month L Jan-15-2025 U.S. Bank, N.A. May-02-2019 Jul-15-2020 $ 50,000 $ (3,100) 2.2459 % One-month L Jan-15-2025 Regions Bank May-02-2019 Jul-15-2020 $ 50,000 $ (3,096) 2.2459 % One-month L Jan-15-2025 Bank of Montreal Jul-16-2019 Jul-15-2020 $ 50,000 $ (2,092) 1.7165 % One-month L Jan-15-2025 U.S. Bank, N.A. Feb-17-2021 Apr-18-2023 $ 150,000 $ 1,794 0.9385 % One-month L Feb-5-2026 Wells Fargo Bank, N.A. Feb-17-2021 Apr-18-2023 $ 75,000 $ 896 0.9365 % One-month L Feb-5-2026 The Toronto-Dominion Bank Feb-17-2021 Apr-18-2023 $ 75,000 $ 902 0.9360 % One-month L Feb-5-2026 The following table summarizes the fair value of the interest rate swaps outstanding as of March 31, 2021 and December 31, 2020. Balance Sheet Line Item (in thousands) Notional Amount March 31, 2021 Fair Value March 31, 2021 Notional Amount December 31, 2020 Fair Value December 31, 2020 Interest rate swaps-Asset $ 300,000 $ 3,592 $ — $ — Interest rate swaps-Liability $ 975,000 $ (32,106) $ 1,125,000 $ (40,656) Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate swaps are to add stability to interest expense and to manage its exposure to interest rate movements. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in accumulated other comprehensive income (loss) and subsequently reclassified into interest expense in the same periods during which the hedged transaction affects earnings. Amounts reported in accumulated other comprehensive income (loss) related to derivatives designated as qualifying cash flow hedges will be reclassified to interest expense as interest payments are made on the Company’s variable rate debt. The Company estimates that approximately $15.4 million will be reclassified from accumulated other comprehensive loss as an increase to interest expense over the next 12 months. The following table summarizes the effect of cash flow hedge accounting and the location in the consolidated financial statements for the three months ended March 31, 2021 and 2020. Three months ended March 31, Effect of Cash Flow Hedge Accounting (in thousands) 2021 2020 Income (loss) recognized in accumulated other comprehensive loss on interest rate swaps $ 7,750 $ (31,087) Loss reclassified from accumulated other comprehensive loss into income as interest expense $ 4,400 $ 896 Total interest expense presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ 15,358 $ 14,864 Credit-risk-related Contingent Features The Company has agreements with each of its derivative counterparties that contain a provision where the Company could be declared in default on its derivative obligations if repayment of the underlying indebtedness is accelerated by the lender due to the Company’s default on the indebtedness. As of March 31, 2021, the Company had not breached the provisions of these agreements and had not posted any collateral related to these agreements. If the Company had breached any of these provisions at March 31, 2021, it could have been required to settle its obligations under the agreement of the interest rate swaps in a net liability position by counterparty plus accrued interest for approximately $29.2 million. Fair Value of Interest Rate Swaps The Company’s valuation of the interest rate swaps is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs including interest rate curves. The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. However, as of March 31, 2021 and December 31, 2020, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The following table summarizes the Company’s financial instruments that are accounted for at fair value on a recurring basis as of March 31, 2021 and December 31, 2020. Fair Value Measurements as of March 31, 2021 Using Balance Sheet Line Item (in thousands) Fair Value March 31, 2021 Level 1 Level 2 Level 3 Interest rate swaps-Asset $ 3,592 $ — $ 3,592 $ — Interest rate swaps-Liability $ (32,106) $ — $ (32,106) $ — Fair Value Measurements as of December 31, 2020 Using Balance Sheet Line Item (in thousands) Fair Value December 31, 2020 Level 1 Level 2 Level 3 Interest rate swaps-Asset $ — $ — $ — $ — Interest rate swaps-Liability $ (40,656) $ — $ (40,656) $ —

Equity

Equity	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity Note [Abstract]
Equity	Equity Preferred Stock On March 1, 2021, the Company gave notice to redeem all 3,000,000 issued and outstanding shares of the 6.875% Series C Cumulative Redeemable Preferred Stock ("Series C Preferred Stock") on March 31, 2021. The Company redeemed the Series C Preferred Stock on March 31, 2021 at a cash redemption price of $25.00 per share, plus accrued and unpaid dividends to but excluding, the redemption date. The Company recognized a deemed dividend to the holders of the Series C Preferred Stock of approximately $2.6 million on the accompanying Consolidated Statements of Operations for the three months ended March 31, 2021 related to redemption costs and the original issuance costs of the Series C Preferred Stock. The Company has no outstanding preferred stock issuances as of March 31, 2021. The following tables summarize the dividends attributable to the Company’s outstanding preferred stock issuances during the three months ended March 31, 2021 and the year ended December 31, 2020. Quarter Ended 2021 Declaration Date Series C Payment Date March 31 January 11, 2021 $ 0.4296875 March 31, 2021 Total $ 0.4296875 Quarter Ended 2020 Declaration Date Series C Payment Date December 31 October 9, 2020 $ 0.4296875 December 31, 2020 September 30 July 9, 2020 0.4296875 September 30, 2020 June 30 April 9, 2020 0.4296875 June 30, 2020 March 31 January 8, 2020 0.4296875 March 31, 2020 Total $ 1.7187500 Common Stock The following table summarizes the terms of the Company’s at-the market (“ATM”) common stock offering program as of March 31, 2021. ATM Common Stock Offering Program Date Maximum Aggregate Offering Price (in thousands) Aggregate Common Stock Available as of March 31, 2021 (in thousands) 2019 $600 million ATM February 14, 2019 $ 600,000 $ 296,244 The table below summarizes the activity under the ATM common stock offering program during the three months ended March 31, 2021 (in thousands, except share data). There was no activity under the ATM common stock offering program during the year ended December 31, 2020. Three months ended March 31, 2021 ATM Common Stock Offering Program Shares Weighted Average Price Per Share Net 2019 $600 million ATM 680,276 $ 32.35 $ 21,785 Total/weighted average 680,276 $ 32.35 $ 21,785 Subsequent to March 31, 2021, the Company sold 602,316 shares under the ATM common stock offering program at a price of $34.24 per share, or $20.6 million, and $33.90 per share net of sales agent fees. In addition, on April 5, 2021, the Company sold 1,446,760 shares on a forward basis under the ATM common stock offering program at a price of $34.56 per share, or $50.0 million, and $34.2144 per share net of sales agent fees. The Company does not initially receive any proceeds from the sale of shares on a forward basis. The Company may elect to cash settle or net share settle the forward sale agreement at any time through the scheduled maturity date of April 5, 2022. The following tables summarize the dividends attributable to the Company’s outstanding shares of common stock that were declared during the three months ended March 31, 2021 and the year ended December 31, 2020. Month Ended 2021 Declaration Date Record Date Per Share Payment Date March 31 January 11, 2021 March 31, 2021 $ 0.120833 April 15, 2021 February 28 January 11, 2021 February 26, 2021 0.120833 March 15, 2021 January 31 January 11, 2021 January 29, 2021 0.120833 February 16, 2021 Total $ 0.362499 Month Ended 2020 Declaration Date Record Date Per Share Payment Date December 31 October 9, 2020 December 31, 2020 $ 0.12 January 15, 2021 November 30 October 9, 2020 November 30, 2020 0.12 December 15, 2020 October 31 October 9, 2020 October 30, 2020 0.12 November 16, 2020 September 30 July 9, 2020 September 30, 2020 0.12 October 15, 2020 August 31 July 9, 2020 August 31, 2020 0.12 September 15, 2020 July 31 July 9, 2020 July 31, 2020 0.12 August 17, 2020 June 30 April 9, 2020 June 30, 2020 0.12 July 15, 2020 May 31 April 9, 2020 May 29, 2020 0.12 June 15, 2020 April 30 April 9, 2020 April 30, 2020 0.12 May 15, 2020 March 31 January 8, 2020 March 31, 2020 0.12 April 15, 2020 February 29 January 8, 2020 February 28, 2020 0.12 March 16, 2020 January 31 January 8, 2020 January 31, 2020 0.12 February 18, 2020 Total $ 1.44 On April 12, 2021, the Company’s board of directors declared the common stock dividends for the months ending April 30, 2021, May 31, 2021, and June 30, 2021 at a monthly rate of $0.120833 per share of common stock. Restricted Shares of Common Stock Restricted shares of common stock granted on January 7, 2021 to certain employees of the Company, subject to the recipient’s continued employment, will vest over four years in equal installments on January 1 of each year beginning in 2022. Refer to Note 8 for a discussion of the restricted shares of common stock granted on January 7, 2021 pursuant to the 2018 performance units. The following table summarizes activity related to the Company’s unvested restricted shares of common stock for the three months ended March 31, 2021 and the year ended December 31, 2020. Unvested Restricted Shares of Common Stock Shares Balance at December 31, 2019 193,045 Granted 75,419 (1) Vested (81,408) (2) Forfeited (2,166) Balance at December 31, 2020 184,890 Granted 90,304 (1) Vested (72,788) (2) Forfeited — Balance at March 31, 2021 202,406 (1) The fair value per share on the grant date of January 7, 2021, February 13, 2020, January 8, 2020, was $29.77, $32.64, and $31.49, respectively. (2) The Company repurchased and retired 25,840 and 34,117 restricted shares of common stock that vested during the three months ended March 31, 2021 and the year ended December 31, 2020, respectively. The weighted average grant date fair value of unvested restricted shares of common stock was $27.70 per share at December 31, 2020, $29.77 per share granted during the three months ended March 31, 2021, $26.76 per share vested during the three months ended March 31, 2021, and $28.96 per share at March 31, 2021. The unrecognized compensation expense associated with the Company’s restricted shares of common stock at March 31, 2021 was approximately $5.0 million and is expected to be recognized over a weighted average period of approximately 2.8 years. The following table summarizes the fair value at vesting for the restricted shares of common stock that vested during the three months ended March 31, 2021 and 2020. Three months ended March 31, Vested Restricted Shares of Common Stock 2021 2020 Vested restricted shares of common stock 72,788 78,010 Fair value of vested restricted shares of common stock (in thousands) $ 2,280 $ 2,463

Noncontrolling Interest

Noncontrolling Interest	3 Months Ended
	Mar. 31, 2021
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling Interest The following table summarizes the activity for noncontrolling interest in the Company for the three months ended March 31, 2021 and the year ended December 31, 2020. Noncontrolling Interest LTIP Units Other Total Noncontrolling Interest Balance at December 31, 2019 1,697,358 2,039,494 3,736,852 2.5 % Granted/Issued 278,806 — 278,806 N/A Forfeited — — — N/A Conversions from LTIP units to Other Common Units (283,741) 283,741 — N/A Redemptions from Other Common Units to common stock — (730,420) (730,420) N/A Balance at December 31, 2020 1,692,423 1,592,815 3,285,238 2.0 % Granted/Issued 405,844 — 405,844 N/A Forfeited — — — N/A Conversions from LTIP units to Other Common Units (97,159) 97,159 — N/A Redemptions from Other Common Units to common stock — (97,159) (97,159) N/A Balance at March 31, 2021 2,001,108 1,592,815 3,593,923 2.2 % The weighted average grant date fair value of outstanding LTIP units was $23.49 per unit at December 31, 2020, $28.13 per unit granted during the three months ended March 31, 2021, $21.47 per unit converted during the three months ended March 31, 2021, and $24.53 per unit at March 31, 2021. LTIP Units LTIP units granted on January 7, 2021 to non-employee, independent directors, subject to the recipient’s continued service, will vest on January 1, 2022. LTIP units granted on January 7, 2021 to certain senior executive officers and senior employees, subject to the recipient’s continued employment, will vest quarterly over four years, with the first vesting date having been March 31, 2021. Refer to Note 8 for a discussion of the LTIP units granted on January 7, 2021 pursuant to the 2018 performance units. The fair value of the LTIP units at the date of grant was determined by a lattice-binomial option-pricing model based on a Monte Carlo simulation. The fair value of the LTIP units are based on Level 3 inputs and are non-recurring fair value measurements. The following table summarizes the assumptions used in valuing such LTIP units granted during the three months ended March 31, 2021 (excluding those LTIP units granted pursuant to the 2018 performance units; refer to Note 8 for details). LTIP Units Assumptions Grant date January 7, 2021 Expected term (years) 10 Expected volatility 34.0 % Expected dividend yield 5.0 % Risk-free interest rate 0.229 % Fair value of LTIP units at issuance (in thousands) $ 4,316 LTIP units at issuance 153,430 Fair value unit price per LTIP unit at issuance $ 28.13 The following table summarizes activity related to the Company’s unvested LTIP units for the three months ended March 31, 2021 and the year ended December 31, 2020. Unvested LTIP Units LTIP Units Balance at December 31, 2019 227,348 Granted 278,806 Vested (294,706) Forfeited — Balance at December 31, 2020 211,448 Granted 405,844 Vested (183,486) Forfeited — Balance at March 31, 2021 433,806 The weighted average grant date fair value of unvested LTIP units was $26.54 per unit at December 31, 2020, $28.13 per unit granted during the three months ended March 31, 2021, $28.08 per unit vested during the three months ended March 31, 2021, and $27.38 per unit at March 31, 2021. The unrecognized compensation expense associated with the Company’s LTIP units at March 31, 2021 was approximately $6.5 million and is expected to be recognized over a weighted average period of approximately 2.0 years. The following table summarizes the fair value at vesting for the LTIP units that vested during the three months ended March 31, 2021 and 2020. Three months ended March 31, Vested LTIP units 2021 2020 Vested LTIP units 183,486 130,187 Fair value of vested LTIP units (in thousands) $ 5,683 $ 3,861

Equity Incentive Plan

Equity Incentive Plan	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Equity Incentive Plan	Equity Incentive Plan On January 7, 2021, the Company granted performance units approved by the compensation committee of the board of directors under the 2011 Plan to certain key employees of the Company. The terms of the performance units granted on January 7, 2021 are substantially the same as the terms of the performance units granted on January 8, 2020, except that the measuring period commenced on January 1, 2021 and ends on December 31, 2023. The fair value of the performance units at the date of grant was determined by a lattice-binomial option-pricing model based on a Monte Carlo simulation. The fair value of the performance units is based on Level 3 inputs and are non-recurring fair value measurements. The performance unit equity compensation expense is recognized ratably from the grant date into earnings over the vesting period. The following table summarizes the assumptions used in valuing the performance units granted during the three months ended March 31, 2021. Performance Units Assumptions Grant date January 7, 2021 Expected volatility 34.4 % Expected dividend yield 5.0 % Risk-free interest rate 0.2271 % Fair value of performance units grant (in thousands) $ 5,522 On December 31, 2020, the measuring period pursuant to the 2018 performance units concluded, and it was determined that the Company’s total stockholder return exceeded the threshold percentage and return hurdle. The compensation committee of the board of directors approved the issuance of 127,671 vested LTIP units and 44,591 vested shares of common stock to the participants (of which 17,731 shares of common stock were repurchased and retired), which were issued on January 7, 2021. The compensation committee of the board of directors also approved the issuance of 124,743 LTIP units and 6,352 restricted shares of common stock that will vest in one year on December 31, 2021, which were issued on January 7, 2021. The unrecognized compensation expense associated with the Company’s performance units at March 31, 2021 was approximately $10.0 million and is expected to be recognized over a weighted average period of approximately 2.1 years. Non-cash Compensation Expense The following table summarizes the amount recorded in general and administrative expenses in the accompanying Consolidated Statements of Operations for the amortization of restricted shares of common stock, LTIP units, performance units, and the Company’s director compensation for the three months ended March 31, 2021 and 2020. Three months ended March 31, Non-Cash Compensation Expense (in thousands) 2021 2020 Restricted shares of common stock $ 651 $ 467 LTIP units 2,408 964 Performance units 1,438 1,307 Director compensation (1) 118 114 Total non-cash compensation expense $ 4,615 $ 2,852 (1) All of the Company’s independent directors elected to receive shares of common stock in lieu of cash for their service during the three months ended March 31, 2021 and 2020. The number of shares of common stock granted is calculated based on the trailing ten days average common stock price ending on the third business day preceding the grant date.

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	Leases Lessor Leases The Company has operating leases in which it is the lessor for its rental property. Certain leases contain variable lease payments based upon changes in the Consumer Price Index (“CPI”). Certain leases contain options to renew or terminate the lease, and options for the lessee to purchase the rental property, all of which are predominately at the sole discretion of the lessee. The following table summarizes the components of rental income recognized during the three months ended March 31, 2021 and 2020 included in the accompanying Consolidated Statements of Operations. Three months ended March 31, Rental Income (in thousands) 2021 2020 Fixed lease payments $ 101,179 $ 90,396 Variable lease payments 29,244 25,006 Straight-line rental income 4,882 3,927 Net decrease to rental income related to above and below market lease amortization (1,480) (990) Total rental income $ 133,825 $ 118,339 The Company evaluates its operating leases to determine if it is probable it will collect substantially all of the lessee's remaining lease payments under the lease term. For those that are not probable of collection, the Company converts to the cash basis of accounting. If the Company subsequently determines that it is probable it will collect substantially all of the lessee's remaining lease payments under the lease term, the Company will reinstate the accrued rent balance adjusting for the amount related to the period when the lease was accounted for on a cash basis. During the three months ended March 31, 2021, this resulted in a net increase of rental income of approximately $0.1 million for the three months ended March 31, 2021 due to the reversal of a net accrued rent liability and tenants converting from cash basis accounting to accrual basis accounting. Additionally, there was $1.4 million of contractual rental income not received from cash basis tenants partially offset by $1.2 million of previously unrecognized rental income payments received from tenants under the cash basis of accounting during the three months ended March 31, 2021. During the three months ended March 31, 2020, the Company did not have any tenants under the cash basis of accounting. As of March 31, 2021 and December 31, 2020, the Company had accrued rental income of approximately $65.4 million and $60.0 million, respectively, included in tenant accounts receivable on the accompanying Consolidated Balance Sheets. As of March 31, 2021 and December 31, 2020, the Company had approximately $29.9 million and $30.1 million, respectively, of total lease security deposits available in the form of existing letters of credit, which are not reflected on the accompanying Consolidated Balance Sheets. As of March 31, 2021 and December 31, 2020, the Company had approximately $0.7 million and $0.7 million, respectively, of lease security deposits available in cash, which are included in restricted cash on the accompanying Consolidated Balance Sheets. The Company’s remaining lease security deposits are commingled in cash and cash equivalents. These funds may be used to settle tenant accounts receivables in the event of a default under the related lease. As of March 31, 2021 and December 31, 2020, the Company’s total liability associated with these lease security deposits was approximately $11.4 million and $11.0 million, respectively, and is included in tenant prepaid rent and security deposits on the accompanying Consolidated Balance Sheets. The Company estimates that billings for real estate taxes, which are the responsibility of certain tenants under the terms of their leases and are not reflected on the Company’s consolidated financial statements, was approximately $5.1 million and $4.8 million for the three months ended March 31, 2021 and 2020, respectively. These amounts would have been the maximum real estate tax expense of the Company, excluding any penalties or interest, had the tenants not met their contractual obligations for these periods. The following table summarizes the maturity of fixed lease payments under the Company’s leases as of March 31, 2021. Year Maturity of Fixed Lease Payments (in thousands) Remainder of 2021 $ 306,057 2022 $ 382,216 2023 $ 339,261 2024 $ 289,904 2025 $ 240,509 Thereafter $ 906,866 Lessee Leases The Company has operating leases in which it is the lessee for ground leases and its corporate office lease. These leases have remaining lease terms of approximately 5.3 years to 48.6 years. Certain ground leases contain options to extend the leases for ten years to 20 years, all of which are reasonably certain to be exercised, and are included in the computation of the Company’s right-of-use assets and operating lease liabilities. The following table summarizes supplemental information related to operating lease right-of-use assets and operating lease liabilities recognized in the Company’s Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020. Operating Lease Term and Discount Rate March 31, 2021 December 31, 2020 Weighted average remaining lease term (years) 29.9 29.9 Weighted average discount rate 6.8 % 6.8 % The following table summarizes the operating lease cost recognized during the three months ended March 31, 2021 and 2020 included in the Company’s Consolidated Statements of Operations. Three months ended March 31, Operating Lease Cost (in thousands) 2021 2020 Operating lease cost included in property expense attributable to ground leases $ 417 $ 331 Operating lease cost included in general and administrative expense attributable to corporate office lease 429 318 Total operating lease cost $ 846 $ 649 The following table summarizes supplemental cash flow information related to operating leases recognized during the three months ended March 31, 2021 and 2020 in the Company’s Consolidated Statements of Cash Flows. Three months ended March 31, Operating Leases (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities (operating cash flows) $ 627 $ 571 Right-of-use assets obtained in exchange for new lease liabilities $ — $ 7,718 The following table summarizes the maturity of operating lease liabilities under the Company’s ground leases and corporate office lease as of March 31, 2021. Year Maturity of Operating Lease Liabilities (1) (in thousands) Remainder of 2021 $ 1,681 2022 3,188 2023 3,248 2024 3,291 2025 3,336 Thereafter 62,365 Total lease payments 77,109 Less: Imputed interest (49,392) Present value of operating lease liabilities $ 27,717 (1) Operating lease liabilities do not include estimates of CPI rent changes required by certain ground lease agreements. Therefore, actual payments may differ than those presented.
Leases	Leases Lessor Leases The Company has operating leases in which it is the lessor for its rental property. Certain leases contain variable lease payments based upon changes in the Consumer Price Index (“CPI”). Certain leases contain options to renew or terminate the lease, and options for the lessee to purchase the rental property, all of which are predominately at the sole discretion of the lessee. The following table summarizes the components of rental income recognized during the three months ended March 31, 2021 and 2020 included in the accompanying Consolidated Statements of Operations. Three months ended March 31, Rental Income (in thousands) 2021 2020 Fixed lease payments $ 101,179 $ 90,396 Variable lease payments 29,244 25,006 Straight-line rental income 4,882 3,927 Net decrease to rental income related to above and below market lease amortization (1,480) (990) Total rental income $ 133,825 $ 118,339 The Company evaluates its operating leases to determine if it is probable it will collect substantially all of the lessee's remaining lease payments under the lease term. For those that are not probable of collection, the Company converts to the cash basis of accounting. If the Company subsequently determines that it is probable it will collect substantially all of the lessee's remaining lease payments under the lease term, the Company will reinstate the accrued rent balance adjusting for the amount related to the period when the lease was accounted for on a cash basis. During the three months ended March 31, 2021, this resulted in a net increase of rental income of approximately $0.1 million for the three months ended March 31, 2021 due to the reversal of a net accrued rent liability and tenants converting from cash basis accounting to accrual basis accounting. Additionally, there was $1.4 million of contractual rental income not received from cash basis tenants partially offset by $1.2 million of previously unrecognized rental income payments received from tenants under the cash basis of accounting during the three months ended March 31, 2021. During the three months ended March 31, 2020, the Company did not have any tenants under the cash basis of accounting. As of March 31, 2021 and December 31, 2020, the Company had accrued rental income of approximately $65.4 million and $60.0 million, respectively, included in tenant accounts receivable on the accompanying Consolidated Balance Sheets. As of March 31, 2021 and December 31, 2020, the Company had approximately $29.9 million and $30.1 million, respectively, of total lease security deposits available in the form of existing letters of credit, which are not reflected on the accompanying Consolidated Balance Sheets. As of March 31, 2021 and December 31, 2020, the Company had approximately $0.7 million and $0.7 million, respectively, of lease security deposits available in cash, which are included in restricted cash on the accompanying Consolidated Balance Sheets. The Company’s remaining lease security deposits are commingled in cash and cash equivalents. These funds may be used to settle tenant accounts receivables in the event of a default under the related lease. As of March 31, 2021 and December 31, 2020, the Company’s total liability associated with these lease security deposits was approximately $11.4 million and $11.0 million, respectively, and is included in tenant prepaid rent and security deposits on the accompanying Consolidated Balance Sheets. The Company estimates that billings for real estate taxes, which are the responsibility of certain tenants under the terms of their leases and are not reflected on the Company’s consolidated financial statements, was approximately $5.1 million and $4.8 million for the three months ended March 31, 2021 and 2020, respectively. These amounts would have been the maximum real estate tax expense of the Company, excluding any penalties or interest, had the tenants not met their contractual obligations for these periods. The following table summarizes the maturity of fixed lease payments under the Company’s leases as of March 31, 2021. Year Maturity of Fixed Lease Payments (in thousands) Remainder of 2021 $ 306,057 2022 $ 382,216 2023 $ 339,261 2024 $ 289,904 2025 $ 240,509 Thereafter $ 906,866 Lessee Leases The Company has operating leases in which it is the lessee for ground leases and its corporate office lease. These leases have remaining lease terms of approximately 5.3 years to 48.6 years. Certain ground leases contain options to extend the leases for ten years to 20 years, all of which are reasonably certain to be exercised, and are included in the computation of the Company’s right-of-use assets and operating lease liabilities. The following table summarizes supplemental information related to operating lease right-of-use assets and operating lease liabilities recognized in the Company’s Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020. Operating Lease Term and Discount Rate March 31, 2021 December 31, 2020 Weighted average remaining lease term (years) 29.9 29.9 Weighted average discount rate 6.8 % 6.8 % The following table summarizes the operating lease cost recognized during the three months ended March 31, 2021 and 2020 included in the Company’s Consolidated Statements of Operations. Three months ended March 31, Operating Lease Cost (in thousands) 2021 2020 Operating lease cost included in property expense attributable to ground leases $ 417 $ 331 Operating lease cost included in general and administrative expense attributable to corporate office lease 429 318 Total operating lease cost $ 846 $ 649 The following table summarizes supplemental cash flow information related to operating leases recognized during the three months ended March 31, 2021 and 2020 in the Company’s Consolidated Statements of Cash Flows. Three months ended March 31, Operating Leases (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities (operating cash flows) $ 627 $ 571 Right-of-use assets obtained in exchange for new lease liabilities $ — $ 7,718 The following table summarizes the maturity of operating lease liabilities under the Company’s ground leases and corporate office lease as of March 31, 2021. Year Maturity of Operating Lease Liabilities (1) (in thousands) Remainder of 2021 $ 1,681 2022 3,188 2023 3,248 2024 3,291 2025 3,336 Thereafter 62,365 Total lease payments 77,109 Less: Imputed interest (49,392) Present value of operating lease liabilities $ 27,717 (1) Operating lease liabilities do not include estimates of CPI rent changes required by certain ground lease agreements. Therefore, actual payments may differ than those presented.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share During the three months ended March 31, 2021 and 2020, there were 198,812 and 181,747, respectively, of unvested restricted shares of common stock on a weighted average basis that were considered participating securities. The following table reconciles the numerators and denominators in the computation of basic and diluted earnings per common share for the three months ended March 31, 2021 and 2020. Three months ended March 31, Earnings Per Share (in thousands, except per share data) 2021 2020 Numerator Net income attributable to common stockholders $ 20,931 $ 62,072 Denominator Weighted average common shares outstanding — basic 158,430 147,570 Effect of dilutive securities (1) Share-based compensation 350 86 Shares issuable under forward sales agreements 346 — Weighted average common shares outstanding — diluted 159,126 147,656 Net income per share — basic and diluted Net income per share attributable to common stockholders — basic $ 0.13 $ 0.42 Net income per share attributable to common stockholders — diluted $ 0.13 $ 0.42

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and ContingenciesThe Company is subject to various legal proceedings and claims that arise in the ordinary course of business. These matters are generally covered by insurance subject to deductible requirements. Management believes that the ultimate settlement of these actions will not have a material adverse effect on the Company’s financial position, results of operations, or cash flows.The Company has letters of credit of approximately $2.6 million as of March 31, 2021 related to construction projects and certain other agreements.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The following non-recognized subsequent events were noted. Subsequent to March 31, 2021, the Company sold 602,316 shares under the ATM common stock offering program at a price of $34.24 per share, or $20.6 million, and $33.90 per share net of sales agent fees. In addition, on April 5, 2021, the Company sold 1,446,760 shares on a forward basis under the ATM common stock offering program at a price of $34.56 per share, or $50.0 million, and $34.2144 per share net of sales agent fees. The Company does not initially receive any proceeds from the sale of

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Quarterly Financial Information	Interim Financial Information The accompanying interim financial statements have been presented in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and with the instructions to Form 10-Q and Regulation S-X for interim financial information. Accordingly, these statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the accompanying interim financial statements include all adjustments, consisting of normal recurring items, necessary for their fair statement in conformity with GAAP. Interim results are not necessarily indicative of results for a full year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the Company’s consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020.
Basis of Presentation	Basis of Presentation The Company’s consolidated financial statements include the accounts of the Company, the Operating Partnership, and their subsidiaries. Interests in the Operating Partnership not owned by the Company are referred to as “Noncontrolling Common Units.” These Noncontrolling Common Units are held by other limited partners in the form of common units (“Other Common Units”) and long term incentive plan units (“LTIP units”) issued pursuant to the STAG Industrial, Inc. 2011 Equity Incentive Plan, as amended and restated (the “2011 Plan”). All significant intercompany balances and transactions have been eliminated in the consolidation of entities. The financial statements of the Company are presented on a consolidated basis for all periods presented.
Share-based Payment Arrangement	Incentive and Equity-Based Employee Compensation Plans On January 7, 2021, the Company adopted the STAG Industrial, Inc. Employee Retirement Vesting Program (the “Vesting Program”) to provide supplemental retirement benefits for eligible employees. For those employees who are retirement eligible or will become retirement eligible during the applicable vesting period under the terms of the Vesting Program, the Company accelerates equity-based compensation through the employee’s six

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Tables)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	The following table presents a reconciliation of cash and cash equivalents and restricted cash reported on the accompanying Consolidated Balance Sheets to amounts reported on the accompanying Consolidated Statements of Cash Flows. Reconciliation of cash and cash equivalents and restricted cash (in thousands) March 31, 2021 December 31, 2020 Cash and cash equivalents $ 18,579 $ 15,666 Restricted cash 3,738 4,673 Total cash and cash equivalents and restricted cash $ 22,317 $ 20,339

Rental Property (Tables)

Rental Property (Tables)	3 Months Ended
	Mar. 31, 2021
Real Estate [Abstract]
Schedule of components of rental property	The following table summarizes the components of rental property as of March 31, 2021 and December 31, 2020. Rental Property (in thousands) March 31, 2021 December 31, 2020 Land $ 500,947 $ 492,783 Buildings, net of accumulated depreciation of $347,390 and $327,043, respectively 3,242,182 3,195,439 Tenant improvements, net of accumulated depreciation of $25,333 and $24,891, respectively 42,290 43,684 Building and land improvements, net of accumulated depreciation of $152,242 and $143,414, respectively 274,135 275,433 Construction in progress 6,759 18,052 Deferred leasing intangibles, net of accumulated amortization of $264,103 and $258,005, respectively 490,532 499,802 Total rental property, net $ 4,556,845 $ 4,525,193
Schedule of real estate properties acquired	The following table summarizes the acquisitions of the Company during the three months ended March 31, 2021. The Company accounted for all of its acquisitions as asset acquisitions. Market (1) Date Acquired Square Feet Number of Buildings Purchase Price Omaha/Council Bluffs, NE-IA January 21, 2021 370,000 1 $ 24,922 Minneapolis/St Paul, MN February 24, 2021 80,655 1 10,174 Long Island, NY February 25, 2021 64,224 1 8,516 Sacramento, CA February 25, 2021 267,284 1 25,917 Little Rock/N Little Rock March 1, 2021 300,160 1 24,317 Cleveland, OH March 18, 2021 170,000 1 6,382 Three months ended March 31, 2021 1,252,323 6 $ 100,228 (1) As defined by CoStar Realty Information Inc (“CoStar”). If the building is located outside of a CoStar defined market, the city and state is reflected.
Summary of allocation of the consideration paid for the acquired assets and liabilities in connection with the acquisition of buildings at the date of acquisition	The following table summarizes the allocation of the consideration paid at the date of acquisition during the three months ended March 31, 2021 for the acquired assets and liabilities in connection with the acquisitions identified in the table above. Acquired Assets and Liabilities Purchase Price (in thousands) Weighted Average Amortization Period (years) of Intangibles at Acquisition Land $ 9,766 N/A Buildings 71,738 N/A Tenant improvements 757 N/A Building and land improvements 3,947 N/A Deferred leasing intangibles - In-place leases 9,813 8.7 Deferred leasing intangibles - Tenant relationships 4,704 11.5 Deferred leasing intangibles - Above market leases 1,975 15.0 Deferred leasing intangibles - Below market leases (2,633) 5.9 Below market assumed debt adjustment 161 18.8 Total purchase price $ 100,228 Less: Mortgage notes assumed (5,103) Net assets acquired $ 95,125
Schedule of pro forma information for acquired properties	The following table summarizes the results of operations for the three months ended March 31, 2021 for the buildings acquired during the three months ended March 31, 2021 included in the Company’s Consolidated Statements of Operations from the date of acquisition. Results of Operations (in thousands) Three months ended March 31, 2021 Total revenue $ 1,287 Net income $ 23
Schedule of Finite-Lived Intangible Assets and Below Market Leases	The following table summarizes the deferred leasing intangibles on the accompanying Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020. March 31, 2021 December 31, 2020 Deferred Leasing Intangibles (in thousands) Gross Accumulated Amortization Net Gross Accumulated Amortization Net Above market leases $ 92,406 $ (35,251) $ 57,155 $ 92,125 $ (33,629) $ 58,496 Other intangible lease assets 662,229 (228,852) 433,377 665,682 (224,376) 441,306 Total deferred leasing intangible assets $ 754,635 $ (264,103) $ 490,532 $ 757,807 $ (258,005) $ 499,802 Below market leases $ 49,664 $ (16,105) $ 33,559 $ 48,521 $ (15,759) $ 32,762 Total deferred leasing intangible liabilities $ 49,664 $ (16,105) $ 33,559 $ 48,521 $ (15,759) $ 32,762 The following table summarizes the amortization expense and the net decrease to rental income for the amortization of deferred leasing intangibles during the three months ended March 31, 2021 and 2020. Three months ended March 31, Deferred Leasing Intangibles Amortization (in thousands) 2021 2020 Net decrease to rental income related to above and below market lease amortization $ 1,480 $ 990 Amortization expense related to other intangible lease assets $ 22,447 $ 20,302
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The following table summarizes the amortization of deferred leasing intangibles over the next five calendar years beginning with 2021 as of March 31, 2021. Year Amortization Expense Related to Other Intangible Lease Assets (in thousands) Net Decrease to Rental Income Related to Above and Below Market Lease Amortization (in thousands) Remainder of 2021 $ 56,927 $ 517 2022 $ 67,300 $ 483 2023 $ 58,725 $ 983 2024 $ 49,665 $ 1,452 2025 $ 42,085 $ 1,283
Below Market Lease, Future Amortization Income	The following table summarizes the amortization of deferred leasing intangibles over the next five calendar years beginning with 2021 as of March 31, 2021. Year Amortization Expense Related to Other Intangible Lease Assets (in thousands) Net Decrease to Rental Income Related to Above and Below Market Lease Amortization (in thousands) Remainder of 2021 $ 56,927 $ 517 2022 $ 67,300 $ 483 2023 $ 58,725 $ 983 2024 $ 49,665 $ 1,452 2025 $ 42,085 $ 1,283

Debt (Tables)

Debt (Tables)	3 Months Ended
	Mar. 31, 2021
Debt Disclosure [Abstract]
Summary of the mortgage notes payable, unsecured term loans and credit facility	The following table summarizes the Company’s outstanding indebtedness, including borrowings under the Company’s unsecured credit facility, unsecured term loans, unsecured notes, and mortgage notes as of March 31, 2021 and December 31, 2020. Loan Principal Outstanding as of March 31, 2021 (in thousands) Principal Outstanding as of December 31, 2020 (in thousands) Interest Rate (1)(2) Maturity Date Prepayment Terms (3) Unsecured credit facility: Unsecured Credit Facility (4) $ 233,000 $ 107,000 L + 0.90% January 12, 2024 i Total unsecured credit facility 233,000 107,000 Unsecured term loans: Unsecured Term Loan A 150,000 150,000 3.38 % March 31, 2022 i Unsecured Term Loan D 150,000 150,000 2.85 % January 4, 2023 i Unsecured Term Loan E 175,000 175,000 3.92 % January 15, 2024 i Unsecured Term Loan F 200,000 200,000 3.11 % January 12, 2025 i Unsecured Term Loan G 300,000 300,000 1.28 % February 5, 2026 i Total unsecured term loans 975,000 975,000 Total unamortized deferred financing fees and debt issuance costs (4,428) (3,889) Total carrying value unsecured term loans, net 970,572 971,111 Unsecured notes: Series F Unsecured Notes 100,000 100,000 3.98 % January 5, 2023 ii Series A Unsecured Notes 50,000 50,000 4.98 % October 1, 2024 ii Series D Unsecured Notes 100,000 100,000 4.32 % February 20, 2025 ii Series G Unsecured Notes 75,000 75,000 4.10 % June 13, 2025 ii Series B Unsecured Notes 50,000 50,000 4.98 % July 1, 2026 ii Series C Unsecured Notes 80,000 80,000 4.42 % December 30, 2026 ii Series E Unsecured Notes 20,000 20,000 4.42 % February 20, 2027 ii Series H Unsecured Notes 100,000 100,000 4.27 % June 13, 2028 ii Total unsecured notes 575,000 575,000 Total unamortized deferred financing fees and debt issuance costs (1,623) (1,719) Total carrying value unsecured notes, net 573,377 573,281 Mortgage notes (secured debt): Wells Fargo Bank, National Association CMBS Loan 48,063 48,546 4.31 % December 1, 2022 iii Thrivent Financial for Lutherans 3,527 3,556 4.78 % December 15, 2023 iv United of Omaha Life Insurance Company 5,087 — 3.71 % October 1, 2039 ii Total mortgage notes 56,677 52,102 Net unamortized fair market value premium (discount) (134) 29 Total unamortized deferred financing fees and debt issuance costs (202) (233) Total carrying value mortgage notes, net 56,341 51,898 Total / weighted average interest rate (5) $ 1,833,290 $ 1,703,290 3.05 % (1) Interest rate as of March 31, 2021. At March 31, 2021, the one-month LIBOR (“L”) was 0.11113%. The current interest rate is not adjusted to include the amortization of deferred financing fees or debt issuance costs incurred in obtaining debt or any unamortized fair market value premiums. The spread over the applicable rate for the Company’s unsecured credit facility and unsecured term loans is based on the Company’s debt rating, as defined in the respective loan agreements. (2) The unsecured term loans have a stated interest rate of one-month LIBOR plus a spread of 1.0%. As of March 31, 2021, one-month LIBOR for the Unsecured Term Loans A, D, E, F, and G was swapped to a fixed rate of 2.38%, 1.85%, 2.92%, 2.11%, and 0.28%, respectively. One-month LIBOR for the Unsecured Term Loan G will be swapped to a fixed rate of 0.94% effective April 18, 2023. (3) Prepayment terms consist of (i) pre-payable with no penalty; (ii) pre-payable with penalty; (iii) pre-payable without penalty three months prior to the maturity date, however can be defeased; and (iv) pre-payable without penalty three months prior to the maturity date. (4) The capacity of the unsecured credit facility is $750.0 million. Deferred financing fees and debt issuance costs, net of accumulated amortization related to the unsecured credit facility of approximately $2.5 million and $1.6 million is included in prepaid expenses and other assets on the accompanying Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020, respectively. The initial maturity date is January 15, 2023, which may be extended pursuant to two six (5) The weighted average interest rate was calculated using the fixed interest rate swapped on the notional amount of $975.0 million of debt, and is not adjusted to include the amortization of deferred financing fees or debt issuance costs incurred in obtaining debt or any unamortized fair market value premiums or discounts.
Interest Income and Interest Expense Disclosure [Table Text Block]	The following table summarizes the costs included in interest expense related to the Company’s debt arrangements on the accompanying Consolidated Statement of Operations for the three months ended March 31, 2021 and 2020. Three months ended March 31, Costs Included in Interest Expense (in thousands) 2021 2020 Amortization of deferred financing fees and debt issuance costs and fair market value premiums/discounts $ 487 $ 676 Facility, unused, and other fees $ 386 $ 364
Schedule of aggregate carrying value of the debt and the corresponding estimate of fair value	The following table summarizes the aggregate principal outstanding under the Company’s debt arrangements and the corresponding estimate of fair value as of March 31, 2021 and December 31, 2020. March 31, 2021 December 31, 2020 Indebtedness (in thousands) Principal Outstanding Fair Value Principal Outstanding Fair Value Unsecured credit facility $ 233,000 $ 233,000 $ 107,000 $ 107,000 Unsecured term loans 975,000 975,000 975,000 978,448 Unsecured notes 575,000 628,674 575,000 628,575 Mortgage notes 56,677 58,841 52,102 54,485 Total principal amount 1,839,677 $ 1,895,515 1,709,102 $ 1,768,508 Net unamortized fair market value premium (discount) (134) 29 Total unamortized deferred financing fees and debt issuance costs (6,253) (5,841) Total carrying value $ 1,833,290 $ 1,703,290

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments [Table Text Block]	The following table summarizes the Company’s outstanding interest rate swaps as of March 31, 2021. All of the Company’s interest rate swaps are designated as qualifying cash flow hedges. Interest Rate Trade Date Effective Date Notional Amount Fair Value Pay Fixed Interest Rate Receive Variable Interest Rate Maturity Date Wells Fargo Bank, N.A. Jan-08-2015 Mar-20-2015 $ 25,000 $ (426) 1.8280 % One-month L Mar-31-2022 The Toronto-Dominion Bank Jan-08-2015 Feb-14-2020 $ 25,000 $ (584) 2.4535 % One-month L Mar-31-2022 Regions Bank Jan-08-2015 Feb-14-2020 $ 50,000 $ (1,178) 2.4750 % One-month L Mar-31-2022 Capital One, N.A. Jan-08-2015 Feb-14-2020 $ 50,000 $ (1,206) 2.5300 % One-month L Mar-31-2022 The Toronto-Dominion Bank Jul-20-2017 Oct-30-2017 $ 25,000 $ (739) 1.8485 % One-month L Jan-04-2023 Royal Bank of Canada Jul-20-2017 Oct-30-2017 $ 25,000 $ (740) 1.8505 % One-month L Jan-04-2023 Wells Fargo Bank, N.A. Jul-20-2017 Oct-30-2017 $ 25,000 $ (740) 1.8505 % One-month L Jan-04-2023 PNC Bank, N.A. Jul-20-2017 Oct-30-2017 $ 25,000 $ (739) 1.8485 % One-month L Jan-04-2023 PNC Bank, N.A. Jul-20-2017 Oct-30-2017 $ 50,000 $ (1,477) 1.8475 % One-month L Jan-04-2023 The Toronto-Dominion Bank Apr-20-2020 Sep-29-2020 $ 75,000 $ (83) 0.2750 % One-month L Apr-18-2023 Wells Fargo Bank, N.A. Apr-20-2020 Sep-29-2020 $ 75,000 $ (90) 0.2790 % One-month L Apr-18-2023 The Toronto-Dominion Bank Apr-20-2020 Mar-19-2021 $ 75,000 $ (83) 0.2750 % One-month L Apr-18-2023 Wells Fargo Bank, N.A. Apr-20-2020 Mar-19-2021 $ 75,000 $ (91) 0.2800 % One-month L Apr-18-2023 The Toronto-Dominion Bank Jul-24-2018 Jul-26-2019 $ 50,000 $ (3,585) 2.9180 % One-month L Jan-12-2024 PNC Bank, N.A. Jul-24-2018 Jul-26-2019 $ 50,000 $ (3,582) 2.9190 % One-month L Jan-12-2024 Bank of Montreal Jul-24-2018 Jul-26-2019 $ 50,000 $ (3,582) 2.9190 % One-month L Jan-12-2024 U.S. Bank, N.A. Jul-24-2018 Jul-26-2019 $ 25,000 $ (1,793) 2.9190 % One-month L Jan-12-2024 Wells Fargo Bank, N.A. May-02-2019 Jul-15-2020 $ 50,000 $ (3,100) 2.2460 % One-month L Jan-15-2025 U.S. Bank, N.A. May-02-2019 Jul-15-2020 $ 50,000 $ (3,100) 2.2459 % One-month L Jan-15-2025 Regions Bank May-02-2019 Jul-15-2020 $ 50,000 $ (3,096) 2.2459 % One-month L Jan-15-2025 Bank of Montreal Jul-16-2019 Jul-15-2020 $ 50,000 $ (2,092) 1.7165 % One-month L Jan-15-2025 U.S. Bank, N.A. Feb-17-2021 Apr-18-2023 $ 150,000 $ 1,794 0.9385 % One-month L Feb-5-2026 Wells Fargo Bank, N.A. Feb-17-2021 Apr-18-2023 $ 75,000 $ 896 0.9365 % One-month L Feb-5-2026 The Toronto-Dominion Bank Feb-17-2021 Apr-18-2023 $ 75,000 $ 902 0.9360 % One-month L Feb-5-2026
Schedule of interest rate swaps	The following table summarizes the fair value of the interest rate swaps outstanding as of March 31, 2021 and December 31, 2020. Balance Sheet Line Item (in thousands) Notional Amount March 31, 2021 Fair Value March 31, 2021 Notional Amount December 31, 2020 Fair Value December 31, 2020 Interest rate swaps-Asset $ 300,000 $ 3,592 $ — $ — Interest rate swaps-Liability $ 975,000 $ (32,106) $ 1,125,000 $ (40,656)
Schedule of the location in the financial statements of the gain or loss recognized on interest rate swaps	The following table summarizes the effect of cash flow hedge accounting and the location in the consolidated financial statements for the three months ended March 31, 2021 and 2020. Three months ended March 31, Effect of Cash Flow Hedge Accounting (in thousands) 2021 2020 Income (loss) recognized in accumulated other comprehensive loss on interest rate swaps $ 7,750 $ (31,087) Loss reclassified from accumulated other comprehensive loss into income as interest expense $ 4,400 $ 896 Total interest expense presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded $ 15,358 $ 14,864
Schedule of financial instruments accounted for at fair value on a recurring basis	The following table summarizes the Company’s financial instruments that are accounted for at fair value on a recurring basis as of March 31, 2021 and December 31, 2020. Fair Value Measurements as of March 31, 2021 Using Balance Sheet Line Item (in thousands) Fair Value March 31, 2021 Level 1 Level 2 Level 3 Interest rate swaps-Asset $ 3,592 $ — $ 3,592 $ — Interest rate swaps-Liability $ (32,106) $ — $ (32,106) $ — Fair Value Measurements as of December 31, 2020 Using Balance Sheet Line Item (in thousands) Fair Value December 31, 2020 Level 1 Level 2 Level 3 Interest rate swaps-Asset $ — $ — $ — $ — Interest rate swaps-Liability $ (40,656) $ — $ (40,656) $ —

Equity (Tables)

Equity (Tables)	3 Months Ended
	Mar. 31, 2021
Stockholders' Equity Note [Abstract]
Dividends Declared [Table Text Block]	The following tables summarize the dividends attributable to the Company’s outstanding preferred stock issuances during the three months ended March 31, 2021 and the year ended December 31, 2020. Quarter Ended 2021 Declaration Date Series C Payment Date March 31 January 11, 2021 $ 0.4296875 March 31, 2021 Total $ 0.4296875 Quarter Ended 2020 Declaration Date Series C Payment Date December 31 October 9, 2020 $ 0.4296875 December 31, 2020 September 30 July 9, 2020 0.4296875 September 30, 2020 June 30 April 9, 2020 0.4296875 June 30, 2020 March 31 January 8, 2020 0.4296875 March 31, 2020 Total $ 1.7187500
Schedule of stock sale activity	The following table summarizes the terms of the Company’s at-the market (“ATM”) common stock offering program as of March 31, 2021. ATM Common Stock Offering Program Date Maximum Aggregate Offering Price (in thousands) Aggregate Common Stock Available as of March 31, 2021 (in thousands) 2019 $600 million ATM February 14, 2019 $ 600,000 $ 296,244 The table below summarizes the activity under the ATM common stock offering program during the three months ended March 31, 2021 (in thousands, except share data). There was no activity under the ATM common stock offering program during the year ended December 31, 2020. Three months ended March 31, 2021 ATM Common Stock Offering Program Shares Weighted Average Price Per Share Net 2019 $600 million ATM 680,276 $ 32.35 $ 21,785 Total/weighted average 680,276 $ 32.35 $ 21,785 Subsequent to March 31, 2021, the Company sold 602,316 shares under the ATM common stock offering program at a price of $34.24 per share, or $20.6 million, and $33.90 per share net of sales agent fees. In addition, on April 5, 2021, the Company sold 1,446,760 shares on a forward basis under the ATM common stock offering program at a price of $34.56 per share, or $50.0 million, and $34.2144 per share net of sales agent fees. The Company does not initially receive any proceeds from the sale of shares on a forward basis. The Company may elect to cash settle or net share settle the forward sale agreement at any time through the scheduled maturity date of April 5, 2022.
Common Stock Dividends Declared [Table Text Block]	The following tables summarize the dividends attributable to the Company’s outstanding shares of common stock that were declared during the three months ended March 31, 2021 and the year ended December 31, 2020. Month Ended 2021 Declaration Date Record Date Per Share Payment Date March 31 January 11, 2021 March 31, 2021 $ 0.120833 April 15, 2021 February 28 January 11, 2021 February 26, 2021 0.120833 March 15, 2021 January 31 January 11, 2021 January 29, 2021 0.120833 February 16, 2021 Total $ 0.362499 Month Ended 2020 Declaration Date Record Date Per Share Payment Date December 31 October 9, 2020 December 31, 2020 $ 0.12 January 15, 2021 November 30 October 9, 2020 November 30, 2020 0.12 December 15, 2020 October 31 October 9, 2020 October 30, 2020 0.12 November 16, 2020 September 30 July 9, 2020 September 30, 2020 0.12 October 15, 2020 August 31 July 9, 2020 August 31, 2020 0.12 September 15, 2020 July 31 July 9, 2020 July 31, 2020 0.12 August 17, 2020 June 30 April 9, 2020 June 30, 2020 0.12 July 15, 2020 May 31 April 9, 2020 May 29, 2020 0.12 June 15, 2020 April 30 April 9, 2020 April 30, 2020 0.12 May 15, 2020 March 31 January 8, 2020 March 31, 2020 0.12 April 15, 2020 February 29 January 8, 2020 February 28, 2020 0.12 March 16, 2020 January 31 January 8, 2020 January 31, 2020 0.12 February 18, 2020 Total $ 1.44
Schedule of activity related to unvested restricted stock awards	The following table summarizes activity related to the Company’s unvested restricted shares of common stock for the three months ended March 31, 2021 and the year ended December 31, 2020. Unvested Restricted Shares of Common Stock Shares Balance at December 31, 2019 193,045 Granted 75,419 (1) Vested (81,408) (2) Forfeited (2,166) Balance at December 31, 2020 184,890 Granted 90,304 (1) Vested (72,788) (2) Forfeited — Balance at March 31, 2021 202,406 (1) The fair value per share on the grant date of January 7, 2021, February 13, 2020, January 8, 2020, was $29.77, $32.64, and $31.49, respectively. (2) The Company repurchased and retired 25,840 and 34,117 restricted shares of common stock that vested during the three months ended March 31, 2021 and the year ended December 31, 2020, respectively.
Schedule of vested restricted shares of common stock activity	The following table summarizes the fair value at vesting for the restricted shares of common stock that vested during the three months ended March 31, 2021 and 2020. Three months ended March 31, Vested Restricted Shares of Common Stock 2021 2020 Vested restricted shares of common stock 72,788 78,010 Fair value of vested restricted shares of common stock (in thousands) $ 2,280 $ 2,463

Noncontrolling Interest (Tables

Noncontrolling Interest (Tables)	3 Months Ended
	Mar. 31, 2021
Noncontrolling Interest [Abstract]
Noncontrolling interest activity	The following table summarizes the activity for noncontrolling interest in the Company for the three months ended March 31, 2021 and the year ended December 31, 2020. Noncontrolling Interest LTIP Units Other Total Noncontrolling Interest Balance at December 31, 2019 1,697,358 2,039,494 3,736,852 2.5 % Granted/Issued 278,806 — 278,806 N/A Forfeited — — — N/A Conversions from LTIP units to Other Common Units (283,741) 283,741 — N/A Redemptions from Other Common Units to common stock — (730,420) (730,420) N/A Balance at December 31, 2020 1,692,423 1,592,815 3,285,238 2.0 % Granted/Issued 405,844 — 405,844 N/A Forfeited — — — N/A Conversions from LTIP units to Other Common Units (97,159) 97,159 — N/A Redemptions from Other Common Units to common stock — (97,159) (97,159) N/A Balance at March 31, 2021 2,001,108 1,592,815 3,593,923 2.2 %
Schedule of share-based payment award, LTIP unit awards, valuation assumptions	The following table summarizes the assumptions used in valuing such LTIP units granted during the three months ended March 31, 2021 (excluding those LTIP units granted pursuant to the 2018 performance units; refer to Note 8 for details). LTIP Units Assumptions Grant date January 7, 2021 Expected term (years) 10 Expected volatility 34.0 % Expected dividend yield 5.0 % Risk-free interest rate 0.229 % Fair value of LTIP units at issuance (in thousands) $ 4,316 LTIP units at issuance 153,430 Fair value unit price per LTIP unit at issuance $ 28.13
Schedule of activity related to unvested LTIP unit awards	The following table summarizes activity related to the Company’s unvested LTIP units for the three months ended March 31, 2021 and the year ended December 31, 2020. Unvested LTIP Units LTIP Units Balance at December 31, 2019 227,348 Granted 278,806 Vested (294,706) Forfeited — Balance at December 31, 2020 211,448 Granted 405,844 Vested (183,486) Forfeited — Balance at March 31, 2021 433,806
Schedule of vested LTIP unit award activity	The following table summarizes the fair value at vesting for the LTIP units that vested during the three months ended March 31, 2021 and 2020. Three months ended March 31, Vested LTIP units 2021 2020 Vested LTIP units 183,486 130,187 Fair value of vested LTIP units (in thousands) $ 5,683 $ 3,861

Equity Incentive Plan (Tables)

Equity Incentive Plan (Tables)	3 Months Ended
	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule of share-based payment award, performance unit awards, valuation assumptions	The following table summarizes the assumptions used in valuing the performance units granted during the three months ended March 31, 2021. Performance Units Assumptions Grant date January 7, 2021 Expected volatility 34.4 % Expected dividend yield 5.0 % Risk-free interest rate 0.2271 % Fair value of performance units grant (in thousands) $ 5,522
Summary of Equity Compensation Expense	The following table summarizes the amount recorded in general and administrative expenses in the accompanying Consolidated Statements of Operations for the amortization of restricted shares of common stock, LTIP units, performance units, and the Company’s director compensation for the three months ended March 31, 2021 and 2020. Three months ended March 31, Non-Cash Compensation Expense (in thousands) 2021 2020 Restricted shares of common stock $ 651 $ 467 LTIP units 2,408 964 Performance units 1,438 1,307 Director compensation (1) 118 114 Total non-cash compensation expense $ 4,615 $ 2,852 (1) All of the Company’s independent directors elected to receive shares of common stock in lieu of cash for their service during the three months ended March 31, 2021 and 2020. The number of shares of common stock granted is calculated based on the trailing ten days average common stock price ending on the third business day preceding the grant date.

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Operating Lease, Lease Income [Table Text Block]	The following table summarizes the components of rental income recognized during the three months ended March 31, 2021 and 2020 included in the accompanying Consolidated Statements of Operations. Three months ended March 31, Rental Income (in thousands) 2021 2020 Fixed lease payments $ 101,179 $ 90,396 Variable lease payments 29,244 25,006 Straight-line rental income 4,882 3,927 Net decrease to rental income related to above and below market lease amortization (1,480) (990) Total rental income $ 133,825 $ 118,339
Lessor, Operating Lease, Payments to be Received, Maturity	The following table summarizes the maturity of fixed lease payments under the Company’s leases as of March 31, 2021. Year Maturity of Fixed Lease Payments (in thousands) Remainder of 2021 $ 306,057 2022 $ 382,216 2023 $ 339,261 2024 $ 289,904 2025 $ 240,509 Thereafter $ 906,866
Lease, Cost [Table Text Block]	The following table summarizes supplemental information related to operating lease right-of-use assets and operating lease liabilities recognized in the Company’s Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020. Operating Lease Term and Discount Rate March 31, 2021 December 31, 2020 Weighted average remaining lease term (years) 29.9 29.9 Weighted average discount rate 6.8 % 6.8 % The following table summarizes the operating lease cost recognized during the three months ended March 31, 2021 and 2020 included in the Company’s Consolidated Statements of Operations. Three months ended March 31, Operating Lease Cost (in thousands) 2021 2020 Operating lease cost included in property expense attributable to ground leases $ 417 $ 331 Operating lease cost included in general and administrative expense attributable to corporate office lease 429 318 Total operating lease cost $ 846 $ 649 The following table summarizes supplemental cash flow information related to operating leases recognized during the three months ended March 31, 2021 and 2020 in the Company’s Consolidated Statements of Cash Flows. Three months ended March 31, Operating Leases (in thousands) 2021 2020 Cash paid for amounts included in the measurement of lease liabilities (operating cash flows) $ 627 $ 571 Right-of-use assets obtained in exchange for new lease liabilities $ — $ 7,718
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The following table summarizes the maturity of operating lease liabilities under the Company’s ground leases and corporate office lease as of March 31, 2021. Year Maturity of Operating Lease Liabilities (1) (in thousands) Remainder of 2021 $ 1,681 2022 3,188 2023 3,248 2024 3,291 2025 3,336 Thereafter 62,365 Total lease payments 77,109 Less: Imputed interest (49,392) Present value of operating lease liabilities $ 27,717 (1) Operating lease liabilities do not include estimates of CPI rent changes required by certain ground lease agreements. Therefore, actual payments may differ than those presented.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted earnings per common share	The following table reconciles the numerators and denominators in the computation of basic and diluted earnings per common share for the three months ended March 31, 2021 and 2020. Three months ended March 31, Earnings Per Share (in thousands, except per share data) 2021 2020 Numerator Net income attributable to common stockholders $ 20,931 $ 62,072 Denominator Weighted average common shares outstanding — basic 158,430 147,570 Effect of dilutive securities (1) Share-based compensation 350 86 Shares issuable under forward sales agreements 346 — Weighted average common shares outstanding — diluted 159,126 147,656 Net income per share — basic and diluted Net income per share attributable to common stockholders — basic $ 0.13 $ 0.42 Net income per share attributable to common stockholders — diluted $ 0.13 $ 0.42

Organization and Description _2

Organization and Description of Business (Details) ft² in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021ft²buildingstate	Dec. 31, 2020
Real Estate Properties [Line Items]
Number of properties	494
Number of states in which the entity owned buildings | state	39
Area (in square feet) | ft²	99.1
STAG Industrial, Inc. [Member]
Real Estate Properties [Line Items]
Ownership interest in Operating Partnership (as a percent)	97.80%	98.00%
Warehouse - Distribution buildings
Real Estate Properties [Line Items]
Number of properties	414
Light Manufacturing buildings
Real Estate Properties [Line Items]
Number of properties	72
Flex/Office Buildings
Real Estate Properties [Line Items]
Number of properties	8

Organization, Consolidation and

Organization, Consolidation and Presentation of Financial Statements - COVID-19 Pandemic (Details)	3 Months Ended
	Mar. 31, 2021USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Rent Deferrals Granted	$ 0

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash and cash equivalents	$ 18,579	$ 15,666
Restricted cash	3,738	4,673
Cash and cash equivalents and restricted cash—end of period	$ 22,317	$ 20,339	$ 341,383	$ 11,864

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Policy Updates (Details) - USD ($) $ in Millions	Jan. 07, 2021	Mar. 31, 2021	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Notification period	6 months
Employee Retirement Vesting Program
Defined Benefit Plan Disclosure [Line Items]
Share-based Payment Arrangement, Accelerated Cost		$ 1.5
Employee Retirement Vesting Program | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Payment Arrangement, Accelerated Cost			$ 2.4

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Taxes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Business Acquisition [Line Items]
Net income	$ 25,348,000	$ 65,038,000
State and local income, excise and franchise taxes	400,000	400,000
Liabilities for uncertain tax positions	0		$ 0
Real Estate Investment Trust
Business Acquisition [Line Items]
Net income	$ 0	$ 0

Rental Property - Summary (Deta

Rental Property - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	$ 4,556,845	$ 4,525,193
Deferred leasing intangible assets, accumulated amortization	264,103	258,005
Land
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	500,947	492,783
Buildings, net of accumulated depreciation of $347,390 and $327,043, respectively
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	3,242,182	3,195,439
Rental property, accumulated depreciation	347,390	327,043
Tenant improvements, net of accumulated depreciation of $25,333 and $24,891, respectively
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	42,290	43,684
Rental property, accumulated depreciation	25,333	24,891
Building and land improvements, net of accumulated depreciation of $152,242 and $143,414, respectively
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	274,135	275,433
Rental property, accumulated depreciation	152,242	143,414
Construction in progress
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	6,759	18,052
Deferred leasing intangibles, net of accumulated amortization of $264,103 and $258,005, respectively
Property Subject to or Available for Operating Lease [Line Items]
Rental property, net	$ 490,532	$ 499,802

Rental Property - Acquisitions

Rental Property - Acquisitions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)ft²building
Business Acquisition [Line Items]
Area (in square feet)	99,100,000
Acquisitions 2021
Business Acquisition [Line Items]
Area (in square feet)	1,252,323
Number of properties | building	6
Business Combination, Consideration Transferred | $	$ 100,228
Bellevue, NE, 1-21-21
Business Acquisition [Line Items]
Area (in square feet)	370,000
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 24,922
Inver Grove Heigh, MN, 2-24-21
Business Acquisition [Line Items]
Area (in square feet)	80,655
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 10,174
Ronkonkoma, NY, 2-25-21
Business Acquisition [Line Items]
Area (in square feet)	64,224
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 8,516
Sacramento, CA, 2-25-21
Business Acquisition [Line Items]
Area (in square feet)	267,284
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 25,917
Bryant, AR, 3-1-1
Business Acquisition [Line Items]
Area (in square feet)	300,160
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 24,317
Maple Heights, OH, 3-18-21
Business Acquisition [Line Items]
Area (in square feet)	170,000
Number of properties | building	1
Business Combination, Consideration Transferred | $	$ 6,382

Rental Property - Acquisition_2

Rental Property - Acquisitions - Allocation of Consideration (Details) - USD ($) $ in Thousands	Feb. 25, 2021	Mar. 31, 2021	Mar. 31, 2020
Allocation of the consideration paid for the acquired assets and liabilities
Land		$ 9,766
Buildings		71,738
Tenant improvements		757
Building and land improvements		3,947
Total purchase price		100,228
Less: Mortgage notes assumed		(5,103)
Net assets acquired		$ 95,125
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt, Fair Value Adjustment, Weighted Average Useful Life		18 years 9 months 18 days
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt, Fair Value Adjustment		$ 161
Assumption of mortgage notes		5,103	$ 0
Ronkonkoma, NY, 2-25-21
Allocation of the consideration paid for the acquired assets and liabilities
Assumption of mortgage notes	$ 5,100
In-place leases
Allocation of the consideration paid for the acquired assets and liabilities
Deferred leasing intangibles		$ (9,813)
Weighted average amortization period of lease intangibles		8 years 8 months 12 days
Tenant relationships
Allocation of the consideration paid for the acquired assets and liabilities
Deferred leasing intangibles		$ (4,704)
Weighted average amortization period of lease intangibles		11 years 6 months
Above market leases
Allocation of the consideration paid for the acquired assets and liabilities
Deferred leasing intangibles		$ (1,975)
Weighted average amortization period of lease intangibles		15 years
Below market leases
Allocation of the consideration paid for the acquired assets and liabilities
Deferred leasing intangibles		$ 2,633
Weighted average amortization period of lease intangibles		5 years 10 months 24 days

Rental Property - Acquisition_3

Rental Property - Acquisitions - Results of Operations (Details) - Acquisitions 2021 $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Business Acquisition [Line Items]
Revenue	$ 1,287
Net income (loss)	$ 23

Rental Property - Disposals (De

Rental Property - Disposals (Details) ft² in Millions	3 Months Ended
	Mar. 31, 2021USD ($)ft²building	Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of buildings disposed | building	494
Area (in square feet) | ft²	99.1
Carrying value of property sold	$ 4,556,845,000		$ 4,525,193,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of buildings disposed | building	4
Area (in square feet) | ft²	0.5
Carrying value of property sold	$ 17,500,000
Contribution to revenue	10,000	$ 400,000
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	(100,000)	$ (100,000)
Net proceeds from sales of rental property	23,900,000
Gain (Loss) on Sale	$ 6,400,000

Rental Property - Deferred Leas

Rental Property - Deferred Leasing Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Deferred leasing intangibles, gross	$ 754,635		$ 757,807
Deferred leasing intangibles assets, accumulated amortization	(264,103)		(258,005)
Deferred leasing intangibles, net	490,532		499,802
Below market lease, gross	49,664		48,521
Below market lease, accumulated amortization	(16,105)		(15,759)
Below market lease, net	33,559		32,762
Net decrease to rental income related to above and below market lease amortization	1,480	$ 990
Above market leases
Finite-Lived Intangible Assets [Line Items]
Deferred leasing intangibles, gross	92,406		92,125
Deferred leasing intangibles assets, accumulated amortization	(35,251)		(33,629)
Deferred leasing intangibles, net	57,155		58,496
Other intangible lease assets
Finite-Lived Intangible Assets [Line Items]
Deferred leasing intangibles, gross	662,229		665,682
Deferred leasing intangibles assets, accumulated amortization	(228,852)		(224,376)
Deferred leasing intangibles, net	433,377		$ 441,306
Amortization expense related to other intangible lease assets	22,447	$ 20,302
Estimated Net Amortization of In-Place Leases, Leasing Commissions and Tenant Relationships
2021	56,927
Finite-Lived Intangible Asset, Expected Amortization, Year One	67,300
2022	58,725
2023	49,665
2024	42,085
Net decrease to rental income related to above and below market lease amortization
Estimated Net Amortization of In-Place Leases, Leasing Commissions and Tenant Relationships
2021	517
Finite-Lived Intangible Asset, Expected Amortization, Year One	483
2022	983
2023	1,452
2024	$ 1,283

Debt - Summary (Details)

Debt - Summary (Details) $ in Thousands	Feb. 25, 2021	Mar. 31, 2021USD ($)extention	Apr. 18, 2023	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Long-term debt, gross		$ 1,839,677		$ 1,709,102
Unamortized debt issuance costs		(6,253)		(5,841)
Debt Instrument, Unamortized Discount (Premium), Net		(134)
Principal outstanding		$ 1,833,290		1,703,290
Weighted average interest rate		3.05%
Interest Rate Swaps
Debt Instrument [Line Items]
Derivative notional amount swapped		$ 975,000
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Stated interest rate		0.11113%
Term Loan | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.00%
$300 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Unsecured Credit Facility
Debt Instrument [Line Items]
Principal outstanding		$ 233,000		107,000
Debt Instrument, Maturity Date		Jan. 12, 2024
Maximum borrowing capacity		$ 750,000
Number Of Extensions | extention		2
Debt Instrument Term Extension Period		6 months
Unsecured Credit Facility | Prepaid Expenses and Other Assets
Debt Instrument [Line Items]
Unamortized debt issuance costs		$ (2,500)		(1,600)
Unsecured Credit Facility | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.90%
Unsecured Term Loans
Debt Instrument [Line Items]
Long-term debt, gross		$ 975,000		975,000
Unamortized debt issuance costs		(4,428)		(3,889)
Principal outstanding		970,572		971,111
Unsecured Term Loans | $150 Million Wells Fargo Unsecured Term Loan A
Debt Instrument [Line Items]
Long-term debt, gross		$ 150,000		150,000
Debt Instrument, Interest Rate, Effective Percentage		3.38%
Debt Instrument, Maturity Date		Mar. 31, 2022
Fixed Interest Rate (as a percent)		2.38%
Unsecured Term Loans | $150 Million Unsecured Term Loan D [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 150,000		150,000
Debt Instrument, Interest Rate, Effective Percentage		2.85%
Debt Instrument, Maturity Date		Jan. 4, 2023
Fixed Interest Rate (as a percent)		1.85%
Unsecured Term Loans | $175 Million Unsecured Term Loan E [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 175,000		175,000
Debt Instrument, Interest Rate, Effective Percentage		3.92%
Debt Instrument, Maturity Date		Jan. 15, 2024
Fixed Interest Rate (as a percent)		2.92%
Unsecured Term Loans | $200 Million Unsecured Term Loan F [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 200,000		200,000
Debt Instrument, Interest Rate, Effective Percentage		3.11%
Debt Instrument, Maturity Date		Jan. 12, 2025
Fixed Interest Rate (as a percent)		2.11%
Unsecured Term Loans | $300 Million Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 300,000		300,000
Debt Instrument, Interest Rate, Effective Percentage		1.28%
Debt Instrument, Maturity Date		Feb. 5, 2026
Fixed Interest Rate (as a percent)		0.28%
Unsecured Term Loans | $300 Million Unsecured Term Loan [Member] | Scenario, Forecast [Member]
Debt Instrument [Line Items]
Fixed Interest Rate (as a percent)			0.94%
Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 575,000		575,000
Unamortized debt issuance costs		(1,623)		(1,719)
Principal outstanding		573,377		573,281
Unsecured Notes | $100 Million Series F Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 100,000		100,000
Stated interest rate		3.98%
Debt Instrument, Maturity Date		Jan. 5, 2023
Unsecured Notes | $50 Million Series A Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 50,000		50,000
Stated interest rate		4.98%
Debt Instrument, Maturity Date		Oct. 1, 2024
Unsecured Notes | $100 Million Series D Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 100,000		100,000
Stated interest rate		4.32%
Debt Instrument, Maturity Date		Feb. 20, 2025
Unsecured Notes | $75 Million Series G Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 75,000		75,000
Stated interest rate		4.10%
Debt Instrument, Maturity Date		Jun. 13, 2025
Unsecured Notes | $50 Million Series B Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 50,000		50,000
Stated interest rate		4.98%
Debt Instrument, Maturity Date		Jul. 1, 2026
Unsecured Notes | $80 Million Series C Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 80,000		80,000
Stated interest rate		4.42%
Debt Instrument, Maturity Date		Dec. 30, 2026
Unsecured Notes | $20 Million Series E Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross		$ 20,000		20,000
Stated interest rate		4.42%
Debt Instrument, Maturity Date		Feb. 20, 2027
Unsecured Notes | $100 Million Series H Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 100,000		100,000
Stated interest rate		4.27%
Debt Instrument, Maturity Date		Jun. 13, 2028
Mortgage Loans Payable
Debt Instrument [Line Items]
Long-term debt, gross		$ 56,677		52,102
Unamortized debt issuance costs		(202)		(233)
Debt Instrument, Unamortized Discount (Premium), Net		(134)		29
Principal outstanding		56,341		51,898
Mortgage Loans Payable | Wells Fargo Bank, National Association CMBS Loan
Debt Instrument [Line Items]
Long-term debt, gross		$ 48,063		48,546
Stated interest rate		4.31%
Debt Instrument, Maturity Date		Dec. 1, 2022
Penalty free prepayment period		3 months
Mortgage Loans Payable | Thrivent Financial for Lutherans Due December 15, 2023 [Member]
Debt Instrument [Line Items]
Long-term debt, gross		$ 3,527		3,556
Stated interest rate		4.78%
Debt Instrument, Maturity Date		Dec. 15, 2023
Penalty free prepayment period		3 months
Mortgage Loans Payable | United of Omaha Life Insurance Company
Debt Instrument [Line Items]
Long-term debt, gross		$ 5,087		$ 0
Stated interest rate		3.71%
Debt Instrument, Maturity Date		Oct. 1, 2039

Debt - 2021 Activity (Details)

Debt - 2021 Activity (Details) - USD ($) $ in Thousands	Feb. 25, 2021	Feb. 05, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Apr. 17, 2020
Debt Instrument [Line Items]
Debt Instrument, Unused Borrowing Capacity, Amount			$ 514,400
Assumption of mortgage notes			5,103	$ 0
Debt Instrument, Unamortized Discount (Premium), Net			$ 134
Debt Instrument, Covenant Compliance			The Company was in compliance with all financial and other covenants		The Company was in compliance with all financial and other covenants
Net book value of properties that are collateral for debt arrangements			$ 89,000		$ 81,400
Fair Value, Nonrecurring
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	4.10%
Ronkonkoma, NY, 2-25-21
Debt Instrument [Line Items]
Assumption of mortgage notes	$ 5,100
Unsecured Credit Facility
Debt Instrument [Line Items]
Debt Issuance Costs, Gross		$ 1,200
Unsecured Credit Facility | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate			0.90%
Interest Expense [Member]
Debt Instrument [Line Items]
Amortization of deferred financing fees			$ 487	676
Line of Credit Facility, Commitment Fee Amount			386	364
Accounts Payable and Accrued Liabilities [Member]
Debt Instrument [Line Items]
Interest payable			7,900	$ 6,300
United of Omaha Life Insurance Company | Ronkonkoma, NY, 2-25-21
Debt Instrument [Line Items]
Assumption of mortgage notes	5,100
Debt Instrument, Unamortized Discount (Premium), Net	$ 200
$300 Million Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Write off of Deferred Debt Issuance Cost			700
Debt Issuance Costs, Gross		$ 1,600
Deferred Financing Accrued Extension Fee						$ 1,100
$300 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Debt Instrument, Basis Spread on Variable Rate, Floor		0.00%
$300 Million Unsecured Term Loan [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.85%
$300 Million Unsecured Term Loan [Member] | Minimum [Member] | Base Rate
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.00%
$300 Million Unsecured Term Loan [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.65%
$300 Million Unsecured Term Loan [Member] | Interest Expense [Member]
Debt Instrument [Line Items]
Write off of Deferred Debt Issuance Cost			$ 300

Debt - Fair Value (Details)

Debt - Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,839,677	$ 1,709,102
Unamortized fair market value premium		29
Unamortized debt issuance costs	(6,253)	(5,841)
Principal outstanding	1,833,290	1,703,290
Long-term debt, fair value	1,895,515	1,768,508
Debt Instrument, Unamortized Discount (Premium), Net	(134)
Unsecured Credit Facility
Debt Instrument [Line Items]
Principal outstanding	233,000	107,000
Long-term debt, fair value	233,000	107,000
Unsecured Term Loans
Debt Instrument [Line Items]
Long-term debt, gross	975,000	975,000
Unamortized debt issuance costs	(4,428)	(3,889)
Principal outstanding	970,572	971,111
Long-term debt, fair value	975,000	978,448
Unsecured Notes
Debt Instrument [Line Items]
Long-term debt, gross	575,000	575,000
Unamortized debt issuance costs	(1,623)	(1,719)
Principal outstanding	573,377	573,281
Long-term debt, fair value	628,674	628,575
Mortgage Loans Payable
Debt Instrument [Line Items]
Long-term debt, gross	56,677	52,102
Unamortized debt issuance costs	(202)	(233)
Principal outstanding	56,341	51,898
Long-term debt, fair value	58,841	54,485
Debt Instrument, Unamortized Discount (Premium), Net	$ (134)	$ 29

Derivative Financial Instrume_3

Derivative Financial Instruments - Risk Management and Unsecured Loan Swaps (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Interest Rate Swaps
Unsecured Term Loan Swaps
Notional amount liabilities	$ 975,000	$ 1,125,000
Notional amount assets	300,000	$ 0
Interest Rate Derivative, Wells Fargo Bank, March 20, 2015
Unsecured Term Loan Swaps
Notional amount liabilities	25,000
Derivative Liability, Fair Value, Gross Liability	$ (426)
Fixed Interest Rate (as a percent)	1.828%
Interest Rate Derivative, The Toronto-Dominion Bank, February 14, 2020
Unsecured Term Loan Swaps
Notional amount liabilities	$ 25,000
Derivative Liability, Fair Value, Gross Liability	$ (584)
Fixed Interest Rate (as a percent)	2.4535%
Interest Rate Derivative, Regions Bank, February 14, 2020
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (1,178)
Fixed Interest Rate (as a percent)	2.475%
Interest Rate Derivative, Capital One, February 14, 2020
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (1,206)
Fixed Interest Rate (as a percent)	2.53%
Interest Rate Derivative, The Toronto-Dominion Bank, October 30, 2017
Unsecured Term Loan Swaps
Notional amount liabilities	$ 25,000
Derivative Liability, Fair Value, Gross Liability	$ (739)
Fixed Interest Rate (as a percent)	1.8485%
Interest Rate Derivative, Royal Bank of Canada, October 30, 2017
Unsecured Term Loan Swaps
Notional amount liabilities	$ 25,000
Derivative Liability, Fair Value, Gross Liability	$ (740)
Fixed Interest Rate (as a percent)	1.8505%
Interest Rate Derivative, Wells Fargo Bank, October 30, 2017
Unsecured Term Loan Swaps
Notional amount liabilities	$ 25,000
Derivative Liability, Fair Value, Gross Liability	$ (740)
Fixed Interest Rate (as a percent)	1.8505%
Interest Rate Derivative, PNC Bank, $25m, October 30, 2017
Unsecured Term Loan Swaps
Notional amount liabilities	$ 25,000
Derivative Liability, Fair Value, Gross Liability	$ (739)
Fixed Interest Rate (as a percent)	1.8485%
Interest Rate Derivative, PNC Bank, $50m, October 30, 2017
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (1,477)
Fixed Interest Rate (as a percent)	1.8475%
Interest Rate Derivative, TD Bank, $75m, Sep 29, 2020
Unsecured Term Loan Swaps
Notional amount liabilities	$ 75,000
Derivative Liability, Fair Value, Gross Liability	$ (83)
Fixed Interest Rate (as a percent)	0.275%
Interest Rate Derivative, Wells Fargo Bank, $75m, Sep 29, 2020
Unsecured Term Loan Swaps
Notional amount liabilities	$ 75,000
Derivative Liability, Fair Value, Gross Liability	$ (90)
Fixed Interest Rate (as a percent)	0.279%
Interest Rate Derivative, TD Bank, $75m, March 19, 2021
Unsecured Term Loan Swaps
Notional amount liabilities	$ 75,000
Derivative Liability, Fair Value, Gross Liability	$ (83)
Fixed Interest Rate (as a percent)	0.275%
Interest Rate Derivative, Wells Fargo Bank, $75m, March 19, 2021
Unsecured Term Loan Swaps
Notional amount liabilities	$ 75,000
Derivative Liability, Fair Value, Gross Liability	$ (91)
Fixed Interest Rate (as a percent)	0.28%
Interest Rate Derivative, The Toronto-Dominion Bank, July 26, 2019 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (3,585)
Fixed Interest Rate (as a percent)	2.918%
Interest Rate Derivative, PNC Bank, July 26, 2019 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (3,582)
Fixed Interest Rate (as a percent)	2.919%
Interest Rate Derivative, Bank of Montreal, July 26, 2019 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (3,582)
Fixed Interest Rate (as a percent)	2.919%
Interest Rate Derivative, US Bank, July 26, 2019 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 25,000
Derivative Liability, Fair Value, Gross Liability	$ (1,793)
Fixed Interest Rate (as a percent)	2.919%
Interest Rate Derivative, Wells Fargo Bank, July 15, 2020 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (3,100)
Fixed Interest Rate (as a percent)	2.246%
Interest Rate Derivative, US Bank, July 15, 2020 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (3,100)
Fixed Interest Rate (as a percent)	2.2459%
Interest Rate Derivative, Regions Bank, July 15, 2020 [Member]
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (3,096)
Fixed Interest Rate (as a percent)	2.2459%
Interest Rate Derivative, Bank of Montreal, July 15, 2020
Unsecured Term Loan Swaps
Notional amount liabilities	$ 50,000
Derivative Liability, Fair Value, Gross Liability	$ (2,092)
Fixed Interest Rate (as a percent)	1.7165%
Interest Rate Derivative, US Bank N.A, April 18, 2023
Unsecured Term Loan Swaps
Notional amount assets	$ 150,000
Derivative Asset, Fair Value, Gross Asset	$ 1,794
Fixed Interest Rate (as a percent)	0.9385%
Interest Rate Derivative, Wells Fargo Bank, April 18, 2021
Unsecured Term Loan Swaps
Notional amount assets	$ 75,000
Derivative Asset, Fair Value, Gross Asset	$ 896
Fixed Interest Rate (as a percent)	0.9365%
Interest Rate Derivative, The Toronto-Dominion Bank, April 18, 2023
Unsecured Term Loan Swaps
Notional amount assets	$ 75,000
Derivative Asset, Fair Value, Gross Asset	$ 902
Fixed Interest Rate (as a percent)	0.936%

Derivative Financial Instrume_4

Derivative Financial Instruments - FV of Interest Rate Swaps (Details) - Interest Rate Swaps - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair value of the interest rate swaps outstanding
Notional amount assets	$ 300,000	$ 0
Fair value - assets	3,592	0
Notional amount liabilities	975,000	1,125,000
Fair Value - liabilities	$ (32,106)	$ (40,656)

Derivative Financial Instrume_5

Derivative Financial Instruments - Cash Flow Hedges and Contingent Features (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash Flow Hedges of Interest Rate Risk
Total interest expense presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded	$ 15,358,000	$ 14,864,000
Interest Rate Swaps
Cash Flow Hedges of Interest Rate Risk
Additional amount reclassified from accumulated other comprehensive income (loss) as a increase (decrease) to interest expense over the next twelve months	15,400,000
Income (loss) recognized in accumulated other comprehensive loss on interest rate swaps	7,750,000	(31,087,000)
Loss reclassified from accumulated other comprehensive loss into income as interest expense	4,400,000	896,000
Total interest expense presented in the Consolidated Statements of Operations in which the effects of cash flow hedges are recorded	15,358,000	$ 14,864,000
Assets Needed for Immediate Settlement, Aggregate Fair Value	$ 29,200,000

Derivative Financial Instrume_6

Derivative Financial Instruments - FV on Recurring Basis (Details) - Interest Rate Swaps - Fair value on recurring basis - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets (liabilities):
Interest rate swaps-Asset	$ 3,592	$ 0
Interest rate swaps-Liability	(32,106)	(40,656)
Level 1
Assets (liabilities):
Interest rate swaps-Asset	0	0
Interest rate swaps-Liability	0	0
Level 2
Assets (liabilities):
Interest rate swaps-Asset	3,592	0
Interest rate swaps-Liability	(32,106)	(40,656)
Level 3
Assets (liabilities):
Interest rate swaps-Asset	0	0
Interest rate swaps-Liability	$ 0	$ 0

Equity - Preferred Stock (Detai

Equity - Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2021	Mar. 01, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020
Class of Stock [Line Items]
Less: redemption of preferred stock			$ 2,582				$ 0
Preferred Stock, Shares Issued	0		0
Series C Preferred Stock
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Shares		3,000,000
Dividend rate (as a percent)			6.875%
Preferred Stock, Redemption Price Per Share	$ 25		$ 25
Less: redemption of preferred stock	$ 2,600
Preferred Stock, Shares Issued	0		0	3,000,000				3,000,000
Preferred Stock, Dividends Per Share, Declared			$ 0.4296875	$ 0.4296875	$ 0.4296875	$ 0.4296875	$ 0.4296875	$ 1.7187500
Dividends Payable, Date Declared			Jan. 11, 2021	Oct. 9, 2020	Jul. 9, 2020	Apr. 9, 2020	Jan. 8, 2020
Dividends Payable, Date to be Paid			Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020

Equity - Common Stock ATM (Deta

Equity - Common Stock ATM (Details) - At The Market Program 2019 $600 Million - USD ($) $ / shares in Units, $ in Thousands	Apr. 05, 2021	May 04, 2021	Mar. 31, 2021	Dec. 31, 2020
Class of Stock [Line Items]
Common Stock Value Authorized under Stock Offering Program			$ 600,000
Common Stock
Class of Stock [Line Items]
Aggregate value of common stock available to be sold under the ATM			$ 296,244
Number of shares sold			680,276	0
Net proceeds from the sale of common stock			$ 21,785
Common Stock | Subsequent Event [Member]
Class of Stock [Line Items]
Number of shares sold	1,446,760	602,316
Shares Issued, Price Per Share	$ 34.56	$ 34.24
Sale of Stock, Price Per Share	$ 34.2144	$ 33.90
Sale of Stock, Gross Consideration Received on Transaction	$ 50,000	$ 20,600
Weighted Average | Common Stock
Class of Stock [Line Items]
Sale of Stock, Price Per Share			$ 32.35

Equity - Common Stock Dividends

Equity - Common Stock Dividends (Details) - $ / shares

Apr. 12, 2021

Mar. 31, 2021

Feb. 28, 2021

Jan. 31, 2021

Dec. 31, 2020

Nov. 30, 2020

Oct. 31, 2020

Sep. 30, 2020

Aug. 31, 2020

Jul. 31, 2020

Jun. 30, 2020

May 31, 2020

Apr. 30, 2020

Mar. 31, 2020

Feb. 29, 2020

Jan. 31, 2020

Mar. 31, 2021

Dec. 31, 2020

Class of Stock [Line Items]

Common Stock, Dividends, Per Share, Declared

$ 0.120833

$ 0.120833

$ 0.120833

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.12

$ 0.362499

$ 1.44

Subsequent Event [Member]

Class of Stock [Line Items]

Common Stock, Dividends, Per Share, Declared

$ 0.120833

Common Stock

Class of Stock [Line Items]

Dividends Payable, Date Declared

Jan. 11, 2021

Jan. 11, 2021

Jan. 11, 2021

Oct. 9, 2020

Oct. 9, 2020

Oct. 9, 2020

Jul. 9, 2020

Jul. 9, 2020

Jul. 9, 2020

Apr. 9, 2020

Apr. 9, 2020

Apr. 9, 2020

Jan. 8, 2020

Jan. 8, 2020

Jan. 8, 2020

Dividends Payable, Date to be Paid

Apr. 15, 2021

Mar. 15, 2021

Feb. 16, 2021

Jan. 15, 2021

Dec. 15, 2020

Nov. 16, 2020

Oct. 15, 2020

Sep. 15, 2020

Aug. 17, 2020

Jul. 15, 2020

Jun. 15, 2020

May 15, 2020

Apr. 15, 2020

Mar. 16, 2020

Feb. 18, 2020

Equity - Restricted Stock (Deta

Equity - Restricted Stock (Details) - Restricted stock - USD ($) $ / shares in Units, $ in Thousands	Jan. 07, 2021	Feb. 13, 2020	Jan. 08, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Shares
Unvested at beginning of period (in shares)				184,890	193,045	193,045
Granted (in shares)				90,304		75,419
Vested (in shares)				(72,788)	(78,010)	(81,408)
Forfeited (in shares)				0		(2,166)
Unvested at end of period (in shares)				202,406		184,890
Fair value of restricted stock per share at grant date	$ 29.77	$ 32.64	$ 31.49	$ 29.77
Stock Repurchased and Retired During Period, Shares				25,840		34,117
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value				$ 28.96		$ 27.70
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value				$ 26.76
Unrecognized compensation costs				$ 5,000
Unrecognized compensation costs, period for recognition				2 years 9 months 18 days
Vested (in shares)				(72,788)	(78,010)	(81,408)
Fair value of shares vested				$ 2,280	$ 2,463

Noncontrolling Interest - Summa

Noncontrolling Interest - Summary (Details) - $ / shares	Jan. 07, 2021	Jan. 08, 2020	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Limited Partner
Noncontrolling interest
Noncontrolling interest ownership percentage			2.20%	2.00%	2.50%
LTIP Units
Noncontrolling interest
stag_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageGrantDateFairValue			$ 24.53	$ 23.49
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 28.13		28.13
stag_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsConvertedWeightedAverageGrantDateFairValue			$ 21.47
LTIP Units | Share-based Compensation Award, Tranche One [Member]
Noncontrolling interest
Vesting period (in years)	4 years
LTIP Units | Independent Director | Share-based Compensation Award, Tranche One [Member]
Noncontrolling interest
Vesting period (in years)		1 year
Noncontrolling Interest - Unit holders in Operating Partnership
Noncontrolling interest
Units outstanding, balance at beginning of period (in units)			3,285,238	3,736,852
Granted/Issued			405,844	278,806
Forfeited			0	0
Conversions from LTIP units to Other Common Units			0	0
Redemptions from Other Common Units to common stock			97,159	730,420
Units outstanding, balance at end of period (in units)			3,593,923	3,285,238
LTIP Units | Noncontrolling Interest - Unit holders in Operating Partnership
Noncontrolling interest
Units outstanding, balance at beginning of period (in units)			1,692,423	1,697,358
Granted/Issued			405,844	278,806
Forfeited			0	0
Conversions from LTIP units to Other Common Units			97,159	283,741
Redemptions from Other Common Units to common stock			0	0
Units outstanding, balance at end of period (in units)			2,001,108	1,692,423
Other Common Units | Noncontrolling Interest - Unit holders in Operating Partnership
Noncontrolling interest
Units outstanding, balance at beginning of period (in units)			1,592,815	2,039,494
Granted/Issued			0	0
Forfeited			0	0
Conversions from LTIP units to Other Common Units			97,159	283,741
Redemptions from Other Common Units to common stock			97,159	730,420
Units outstanding, balance at end of period (in units)			1,592,815	1,592,815

Noncontrolling Interest - LTIP

Noncontrolling Interest - LTIP FV Assumptions (Details) - LTIP Units - USD ($)	Jan. 07, 2021	Jan. 08, 2020	Mar. 31, 2021	Dec. 31, 2020
Assumptions
Expected term (years)	10 years
Expected volatility	34.00%
Expected dividend yield	5.00%
Risk-free interest rate	0.229%
Fair value of LTIP units at issuance (in thousands)	$ 4,316,000
Granted (in shares)	153,430		405,844	278,806
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 28.13		$ 28.13
Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Independent Director | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)		1 year

Noncontrolling Interest - LTI_2

Noncontrolling Interest - LTIP Units (Details) - LTIP Units - USD ($) $ / shares in Units, $ in Thousands	Jan. 07, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Units
Unvested at beginning of period (in shares)		211,448	227,348	227,348
Granted	153,430	405,844		278,806
Vested (in units)		(183,486)	(130,187)	(294,706)
Forfeited (in units)		0		0
Unvested at end of period (in shares)		433,806		211,448
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value		$ 27.38		$ 26.54
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 28.13	28.13
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value		$ 28.08
Unrecognized compensation costs		$ 6,500
Unrecognized compensation costs, period for recognition		2 years
Vested (in units)		183,486	130,187	294,706
Fair value of units vested		$ 5,683	$ 3,861

Equity Incentive Plan - Perform

Equity Incentive Plan - Performance Plan Assumptions (Details) - Performance shares $ in Thousands	Jan. 07, 2021USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	34.40%
Expected dividend yield	5.00%
Risk-free interest rate	0.2271%
Fair value of performance units grant (in thousands)	$ 5,522

Equity Incentive Plan - 2021 Ac

Equity Incentive Plan - 2021 Activity (Details) - USD ($) $ in Millions	Jan. 07, 2021	Mar. 31, 2021	Dec. 31, 2020
LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	153,430	405,844	278,806
Unrecognized compensation costs		$ 6.5
Unrecognized compensation costs, period for recognition		2 years
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	4 years
Stock Repurchased and Retired During Period, Shares		25,840	34,117
Granted		90,304	75,419
Unrecognized compensation costs		$ 5
Unrecognized compensation costs, period for recognition		2 years 9 months 18 days
Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs		$ 10
Unrecognized compensation costs, period for recognition		2 years 1 month 6 days
Performance Units Granted in 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	1 year
Performance Units Granted in 2018 | LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of vested LTIP units and shares	127,671
Stock Repurchased and Retired During Period, Shares	17,731
Granted	124,743
Performance Units Granted in 2018 | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of vested LTIP units and shares	44,591
Performance Units Granted in 2018 | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	6,352

Equity Incentive Plan - Equity

Equity Incentive Plan - Equity Non-cash Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
General and Administrative Expenses
Equity Incentive Plan
Share-based compensation	$ 4,615	$ 2,852
Restricted stock | General and Administrative Expenses
Equity Incentive Plan
Share-based compensation	651	467
LTIP Units | General and Administrative Expenses
Equity Incentive Plan
Share-based compensation	2,408	964
Performance shares | General and Administrative Expenses
Equity Incentive Plan
Share-based compensation	1,438	1,307
Independent Director | General and Administrative Expenses
Equity Incentive Plan
Share-based compensation	$ 118	$ 114
Common Stock | Independent Director
Equity Incentive Plan
Number of days of average trailing stock price used to calculate number of shares of common stock granted	10 days	10 days

Leases - Rental Income (Details

Leases - Rental Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases [Abstract]
Fixed lease payments	$ 101,179	$ 90,396
Variable lease payments	29,244	25,006
Straight-line rental income	4,882	3,927
Net decrease to rental income related to above and below market lease amortization	(1,480)	(990)
Rental income	$ 133,825	$ 118,339

Leases - Tenant Accounts Receiv

Leases - Tenant Accounts Receivable (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual Rent Adjustment To Rental Income Resulting From Lease Collectibility Assessment	$ 1.4
Contractual Rent Adjustment To Rental Income	1.2
Accrued Rent Adjustment To Rental Income Resulting From Lease Collectibility Assessment	(0.1)
Lease Security Deposits Available in Letters of Credit	29.9		$ 30.1
Lease security deposits in restricted cash	0.7		0.7
Lease security deposits included in tenant prepaid rent and security deposits on the Balance Sheet	11.4		11
Real Estate Taxes, Tenant Responsibility	5.1	$ 4.8
Accrued Income Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred Rent Receivables, Net	$ 65.4		$ 60

Leases - Maturity of Fixed Leas

Leases - Maturity of Fixed Lease Payments (Details) $ in Thousands	Mar. 31, 2021USD ($)
Leases [Abstract]
2021	$ 306,057
2022	382,216
2022	339,261
2023	289,904
2024	240,509
Thereafter	$ 906,866

Leases - Lessee Leases (Details

Leases - Lessee Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	29 years 10 months 24 days		29 years 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	6.80%		6.80%
Lease, Cost	$ 846	$ 649
Operating Lease, Payments	627	571
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 0	7,718
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	5 years 3 months 18 days
Lessee, Operating Lease, Renewal Term	10 years
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	48 years 7 months 6 days
Lessee, Operating Lease, Renewal Term	20 years
Operating Expense [Member]
Lessee, Lease, Description [Line Items]
Lease, Cost	$ 417	331
General and Administrative Expenses
Lessee, Lease, Description [Line Items]
Lease, Cost	$ 429	$ 318

Leases - Maturity of Operating

Leases - Maturity of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
2021	$ 1,681
2022	3,188
2022	3,248
2023	3,291
2024	3,336
Thereafter	62,365
Lessee, Operating Lease, Liability, Payments, Due	77,109
Less: Imputed interest	(49,392)
Operating lease liabilities	$ 27,717	$ 27,898

Earnings Per Share (Details)

Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Participating securities	198,812	181,747

Earnings Per Share - Reconcilia

Earnings Per Share - Reconciliation of Numerator and Denominator (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Numerator
Net income attributable to common stockholders	$ 20,931	$ 62,072
Denominator
Weighted average common shares outstanding — basic	158,430	147,570
Shares issuable under forward sales agreements	346	0
Weighted average common shares outstanding — diluted	159,126	147,656
Net income per share — basic and diluted
Net income per share attributable to common stockholders — basic	$ 0.13	$ 0.42
Net income per share attributable to common stockholders — diluted	$ 0.13	$ 0.42
Restricted stock
Net income per share — basic and diluted
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	199	182
Stock Compensation Plan
Denominator
Share-based compensation	350	86

Commitments and Contingencies -

Commitments and Contingencies - Agreements (Details) $ in Millions	Mar. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Letters of credit outstanding	$ 2.6

Subsequent Events - ATM (Detail

Subsequent Events - ATM (Details) - Common Stock - At The Market Program 2019 $600 Million - USD ($) $ / shares in Units, $ in Thousands	Apr. 05, 2021	May 04, 2021	Mar. 31, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Proceeds from sales of common stock (in shares)			680,276	0
Net proceeds from the sale of common stock			$ 21,785
Subsequent Event [Member]
Subsequent Event [Line Items]
Proceeds from sales of common stock (in shares)	1,446,760	602,316
Shares Issued, Price Per Share	$ 34.56	$ 34.24
Sale of Stock, Gross Consideration Received on Transaction	$ 50,000	$ 20,600
Sale of Stock, Price Per Share	$ 34.2144	$ 33.90