Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
OPERATING ACTIVITIES
Net income	$ 23,096	$ 75,513	$ 47,118	$ 79,828
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			99,905	95,188
Other amortization			1,728	2,510
Share-based compensation			5,647	5,004
Amortization of straight-line rent receivable (lessor)			(3,024)	(1,807)
Amortization of straight-line rent on operating leases (lessee)			735	749
Gain on sales of real estate properties			(39,860)	(68,218)
Impairment of real estate properties			5,912
Equity loss from unconsolidated joint ventures	146	116	220	127
Distributions from unconsolidated joint ventures				184
Changes in operating assets and liabilities:
Other assets, including right-of-use-assets			(4,746)	(1,272)
Accounts payable and accrued liabilities			(10,418)	(5,902)
Other liabilities			2,412	(1,152)
Net cash provided by operating activities			105,629	105,239
INVESTING ACTIVITIES
Acquisitions of real estate			(100,121)	(87,417)
Development of real estate			(1,415)	(2,678)
Additional long-lived assets			(41,839)	(44,316)
Investments in unconsolidated joint ventures			(45,018)
Investment in financing receivable			(104,648)
Proceeds from sales of real estate properties			90,144
Net cash used in investing activities			(202,897)	(134,411)
FINANCING ACTIVITIES
Net borrowings (repayments) on unsecured credit facility			13,000	(293,000)
Borrowings on term loan				150,000
Borrowings of notes and bonds payable				298,995
Repayments on notes and bonds payable			(1,925)	(31,698)
Dividends paid			(86,803)	(80,926)
Net proceeds from issuance of common stock			179,381	40,169
Common stock redemptions			(2,014)	(892)
Settlement of treasury rate locks				(4,267)
Debt issuance and assumption costs			(252)	(3,018)
Payments made on finance leases	(321)	(2,847)	(683)	(3,168)
Net cash provided by financing activities			100,704	72,195
Increase in cash and cash equivalents			3,436	43,023
Cash and cash equivalents at beginning of period			15,303	657	$ 657
Cash and cash equivalents at end of period	$ 18,739	$ 43,680	18,739	43,680	$ 15,303
Supplemental Cash Flow Information
Interest paid			24,659	26,101
Invoices accrued for construction, tenant improvements and other capitalized costs			19,506	10,013
Mortgage notes payable assumed upon acquisition (adjusted to fair value)				19,269
Capitalized interest			$ 154	$ 706