CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 31,557	$ (38,289)	$ 34,648	$ (33,422)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization			93,601	101,627
Straight-line rents			(4,244)	(4,022)
Non-cash lease expense			2,887	2,382
Net unrealized holding gains on investments			(55,796)	(57,031)
Distributions of operating income from unconsolidated affiliates			2,004	2,829
Equity in (earnings) losses of unconsolidated affiliates	(644)	624	(4,013)	155
Stock compensation expense			9,780	8,551
Amortization of financing costs			3,901	4,040
Impairment charges	9,925	0	9,925	51,549
Gain on disposition of properties	0	(24)	(10,521)	(509)
Allowance for credit loss			973	20,509
Termination of ground lease			(3,615)	0
Adjustments to straight-line rent reserves			254	19,678
Other, net			(5,319)	(3,228)
Changes in assets and liabilities:
Other liabilities			1,833	(7,736)
Lease liability - operating leases			(2,653)	(957)
Prepaid expenses and other assets			(5,579)	(1,435)
Rents receivable			4,104	(27,489)
Accounts payable and accrued expenses			220	7,015
Net cash provided by operating activities			72,390	82,506
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of real estate			(63,425)	(21,208)
Development, construction and property improvement costs			(27,197)	(29,374)
Proceeds from the disposition of properties, net			63,901	14,182
Investments in and advances to unconsolidated affiliates and other			(6,111)	(3,662)
Return of capital from unconsolidated affiliates and other			10,671	9,054
Issuance of notes receivable			(57,957)	(59,000)
Return of deposits for properties under contract			(0)	187
Payment of deferred leasing costs			(3,509)	(5,422)
Change in control of previously unconsolidated affiliate			0	950
Net cash used in investing activities			(83,627)	(94,293)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on mortgage and other notes			(69,766)	(18,981)
Principal payments on unsecured debt			(160,387)	(123,750)
Proceeds received on mortgage and other notes			12,654	5,523
Proceeds from unsecured debt			211,854	215,554
Payments of finance lease obligations			(63)	(903)
Proceeds from the sale (repurchase) of Common Shares			45,865	(22,386)
Capital contributions from noncontrolling interests			26,627	36,736
Distributions to noncontrolling interests			(23,781)	(28,418)
Dividends paid to Common Shareholders			(26,208)	(50,182)
Deferred financing and other costs			(7,296)	(1,635)
Net cash provided by financing activities			9,499	11,558
Decrease in cash and restricted cash			(1,738)	(229)
Cash of $19,232 and $15,845 and restricted cash of $14,692 and $14,165, respectively, beginning of period			33,924	30,010	$ 30,010
Cash of $17,359 and $16,108 and restricted cash of $14,827 and $13,673, respectively, end of period	$ 32,186	$ 29,781	32,186	29,781	$ 33,924
Supplemental disclosure of cash flow information
Cash paid during the period for interest, net of capitalized interest of $2,723 and $8,430 respectively			31,807	40,470
Cash paid for income taxes, net of refunds			253	282
Supplemental disclosure of non-cash investing and financing activities
Right-of-use, assets operating leases modified in exchange for operating lease liabilities			412	0
Assumption of accounts payable and accrued expenses through acquisition of real estate			523	116
Acquisition of real estate through assumption of debt			31,802
Distribution declared and payable on October 15, 2021 and 2020, respectively			14,314	123
Settlement of note receivable through cancellation of OP Units			479
Right-of-use assets, finance leases obtained in exchange for assets under capital lease				(70,427)
Right-of-use assets, operating leases exchanged for operating lease liabilities				33,189
Right of use assets operating leases obtained (terminated) in exchange for finance lease liabilities				(1,432)
Change in control of previously unconsolidated (consolidated) investment
Increase in real estate				(135,190)
Decrease in investments in and advances to unconsolidated affiliates				96,816
Change in other assets and liabilities				1,238
Acquisition of noncontrolling interest asset				(588)
Decrease in notes receivable				38,674
Increase in cash and restricted cash upon change of control				$ 950