Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 79,795	$ 55,516	$ 63,289
Adjustments to reconcile net income to net cash provided by operating activities
Straight-line rents	(361)	(2,597)	(3,459)
Amortization of lease intangibles	(5,420)	(4,682)	(3,694)
Depreciation and amortization	45,875	44,015	40,816
Loss on extinguishment of debt	0	189	0
Gain on sales of real estate investments	(26,766)	(9,391)	(28,610)
Deferred financing cost amortization	1,391	1,562	1,442
Deferred senior secured loan fee amortization	(57)	(531)	(392)
Stock-based compensation	9,826	10,644	9,270
Changes in assets and liabilities
Other assets	(3,911)	(1,579)	(1,531)
Accounts payable and other liabilities	678	1,542	468
Net cash provided by operating activities	101,050	94,688	77,599
CASH FLOWS FROM INVESTING ACTIVITIES
Cash paid for property acquisitions	(98,088)	(238,661)	(221,806)
Proceeds from sales of real estate investments, net	70,685	47,133	79,594
Additions to construction in progress	(8,989)	(27,884)	(9,668)
Additions to buildings, improvements and leasing costs	(31,611)	(32,070)	(28,977)
Cash paid for senior secured loan	0	0	(55,000)
Cash paid for senior secured loan	15,915	0	0
Origination and other fees received on senior secured loan	0	0	900
Net cash used in investing activities	(52,088)	(251,482)	(234,957)
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of common stock	64,767	278,058	208,949
Issuance costs on issuance of common stock	(940)	(4,023)	(3,030)
Repurchase of common stock related to employee awards	(9,837)	(3,959)	(3,870)
Borrowings on credit facility	0	17,000	204,000
Payments on credit facility	0	(36,000)	(185,000)
Payments on term loans payable	0	(50,000)	0
Borrowings on senior unsecured notes	0	100,000	0
Payments on mortgage loans payable	(33,077)	(1,514)	(19,201)
Payment of deferred financing costs	0	(943)	(1,366)
Dividends paid to common stockholders	(74,778)	(63,565)	(51,445)
Net cash (used in) provided by financing activities	(53,865)	235,054	149,037
Net (decrease) increase in cash and cash equivalents and restricted cash	(4,903)	78,260	(8,321)
Cash and cash equivalents and restricted cash at beginning of year	112,739	34,479	42,800
Cash and cash equivalents and restricted cash at end of year	107,836	112,739	34,479
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest, net of capitalized interest	16,315	18,351	19,787
Supplemental disclosures of non-cash transactions
Accounts payable related to capital improvements	10,552	12,498	10,712
Non-cash issuance of common stock to the deferred compensation plan	(7,546)	0	0
Non-cash issuance of common stock to the deferred compensation plan	0	(39,085)	0
Non-cash repayment of senior secured loan	0	39,085	0
Lease liability arising from recognition of right-of-use asset	0	647	0
Reconciliation of cash paid for property acquisitions
Acquisition of properties	100,391	250,506	227,058
Assumption of other assets and liabilities	(2,303)	(11,845)	(5,252)
Net cash paid for property acquisitions	$ 98,088	$ 238,661	$ 221,806