Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
OPERATING ACTIVITIES
Net income		$ 36,959	$ 32,258	$ 23,492
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of buildings and tenant improvements		43,671	37,839	30,395
Amortization of leasing costs, in-place lease intangibles and below market ground rents - operating leases		16,301	16,725	9,518
Accrued straight-line rental revenue		(5,927)	(3,402)	(2,731)
Amortization of leasing incentives and above or below-market rents		(814)	(629)	(266)
Amortization of right-of-use assets - finance leases		586	377	0
Accrued straight-line ground rent expense		100	(16)	214
Provision for unrealized credit losses		256	0	0
Adjustment for uncollectable accounts		3,842	511	419
Noncash stock compensation		2,378	1,613	1,281
Impairment charges		666	252	1,619
Noncash interest expense		2,204	1,258	1,116
Interest expense on finance leases		915	568	0
Gain on real estate dispositions		(6,388)	(4,699)	(4,254)
Adjustment for Annapolis Junction modification fee	[1]	0	(4,489)	4,489
Change in the fair value of interest rate derivatives		1,130	3,599	951
Equity in income of unconsolidated real estate entities		0	(273)	(372)
Changes in operating assets and liabilities:
Property assets		(5,960)	(2,499)	(3,539)
Property liabilities		5,762	3,368	1,720
Construction assets		(2,302)	(20,356)	7,554
Construction liabilities		13,708	18,671	(15,248)
Interest receivable		(15,908)	(12,947)	(271)
Net cash provided by operating activities		91,179	67,729	56,087
INVESTING ACTIVITIES
Development of real estate investments		(63,485)	(133,445)	(133,791)
Tenant and building improvements		(10,077)	(19,721)	(11,723)
Acquisitions of real estate investments, net of cash received		(35,151)	(138,380)	(57,544)
Dispositions of real estate investments, net of selling costs		96,459	32,944	34,673
Notes receivable issuances		(24,484)	(54,555)	(58,208)
Notes receivable paydowns		16,340	22,522	1,165
Leasing costs		(3,425)	(3,893)	(4,607)
Leasing incentives		(1,326)	0	(108)
Contributions to equity method investments		(1,078)	(535)	(10,420)
Net cash used for investing activities		(26,227)	(295,063)	(240,563)
FINANCING ACTIVITIES
Proceeds from issuance of cumulative redeemable perpetual preferred stock, net		101,460	61,001	0
Proceeds from issuance of common stock, net		19,650	96,845	65,244
Common shares tendered for tax withholding		(569)	(369)	(409)
Debt issuances, credit facility and construction loan borrowings		176,619	427,286	349,580
Debt and credit facility repayments, including principal amortization		(299,318)	(270,851)	(173,855)
Debt issuance costs		(609)	(5,546)	(1,457)
Acquisition of NCI in consolidated RE investments		(5,002)	0	0
Redemption of operating partnership units		(2,729)	0	(2,595)
Dividends and distributions		(47,603)	(61,504)	(50,897)
Net cash provided by (used for) financing activities		(58,101)	246,862	185,611
Net increase in cash, cash equivalents, and restricted cash		6,851	19,528	1,135
Cash, cash equivalents, and restricted cash, beginning of period	[2]	43,579	24,051	22,916
Cash, cash equivalents, and restricted cash, end of period	[2]	50,430	43,579	24,051
Supplemental cash flow information:
Cash paid for interest		28,554	28,878	17,319
Cash refunded for income taxes		167	247	31
Increase (decrease) in dividends payable		(5,724)	3,950	1,640
Common shares and OP units issued for acquisitions		6,099	73,169	1,702
(Decrease) increase in accrued capital improvements and development costs		(14,324)	(12,666)	18,310
Operating Partnership units redeemed for common shares		8,866	2,756	3,715
Note payable recorded for mandatorily redeemable partnership interest		3,829	0	0
Debt assumed at fair value in conjunction with real estate purchases		122,300	101,390	0
Note receivable extinguished in conjunction with real estate purchase		42,270	31,252	0
Equity method investment redeemed for real estate acquisition		0	23,011	0
Noncontrolling interest in acquired real estate entity		0	4,870	0
Note payable issued in acquisition of noncontrolling interest in real estate investment		6,130	0	0
Recognition of operating lease ROU assets	[3]	0	33,965	0
Recognition of operating lease liabilities	[3]	0	41,631	0
Recognition of finance lease right-of-use assets		0	24,500	0
Recognition of finance lease liabilities		0	17,871	0
De-recognition of operating lease ROU assets - lease termination		0	440	0
De-recognition of operating lease liabilities - lease termination		$ 0	$ 440	$ 0

[1] Borrower paid $5.0 million in 2018 in exchange for the Company's purchase option. This was accounted for as a loan modification fee; interest income was recognized as additional interest income on the note receivable over the one-year remaining term.

[2] The following table sets forth the items from the Company's Consolidated Balance Sheets that are included in cash, cash equivalents, and restricted cash in the consolidated statements of cash flows:  As of December 31, 20202019Cash and cash equivalents$40,998 $39,232  Restricted cash (a) 9,432 4,347 Cash, cash equivalents, and restricted cash$50,430 $43,579  (a) Restricted cash represents amounts held by lenders for real estate taxes, insurance, and reserves for capital improvements.

[3] Amounts attributable to 2019 are net of $0.4 million related to the Company's preexisting lease at the Thames Street Wharf property, which was acquired on June 26, 2019.