CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net (loss) income	$ (38,289)	$ 8,840	$ (33,422)	$ 6,539
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization			101,627	92,807
Net unrealized holding gains on investments			(57,031)
Distributions of operating income from unconsolidated affiliates			2,829	8,654
Equity in earnings and gains of unconsolidated affiliates	624	(1,299)	155	(7,129)
Stock compensation expense			8,551	7,361
Amortization of financing costs			4,040	5,769
Impairment charges		321	51,549	1,721
Gain on disposition of properties	(24)	(12,056)	(509)	(14,070)
Credit loss and straight-line rent reserves			39,882
Deferred gain on tax credits				(5,034)
Other, net			(2,923)	(7,804)
Changes in assets and liabilities:
Other liabilities			(7,736)	(6,071)
Prepaid expenses and other assets			(1,435)	10,271
Rents receivable			(31,511)	870
Accounts payable and accrued expenses			7,015	1,303
Net cash provided by operating activities			81,081	95,187
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of real estate			(21,208)	(256,647)
Development, construction and property improvement costs			(27,949)	(77,636)
(Issuance) redemption of notes receivable			(59,000)	15,250
Proceeds from the disposition of properties, net			14,182	80,120
Investments in and advances to unconsolidated affiliates and other			(3,662)	(154,256)
Return of capital from unconsolidated affiliates and other			9,054	38,359
Return (payment) of deposits for properties under contract			187	1,060
Payment of deferred leasing costs			(5,422)	(5,874)
Change in control of previously unconsolidated affiliate			950
Net cash used in investing activities			(92,868)	(359,624)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on mortgage and other notes			(18,981)	(166,865)
Principal payments on unsecured debt			(123,750)	(352,195)
Proceeds received on mortgage and other notes			5,523	183,556
Proceeds from unsecured debt			215,554	444,575
Payments of finance lease obligations			(903)	(2,125)
(Repurchase) proceeds from the sale of Common Shares			(22,386)	135,750
Capital contributions from noncontrolling interests			36,736	161,628
Distributions to noncontrolling interests			(28,418)	(39,917)
Dividends paid to Common Shareholders			(50,182)	(69,641)
Deferred financing and other costs			(1,635)	(4,170)
Net cash provided by financing activities			11,558	290,596
(Decrease) increase in cash and restricted cash			(229)	26,159
Cash of $15,845 and $21,268 and restricted cash of $14,165 and $13,580, respectively, beginning of period			30,010	34,848	$ 34,848
Cash of $16,108 and $27,765 and restricted cash of $13,673 and $12,527, respectively, end of period	$ 29,781	$ 61,007	29,781	61,007	$ 30,010
Supplemental disclosure of cash flow information
Cash paid during the period for interest, net of capitalized interest of $6,270 and $8,430 respectively			40,470	53,586
Cash paid for income taxes, net of refunds			282	730
Supplemental disclosure of non-cash investing and financing activities
Assumption of accounts payable and accrued expenses through acquisition of real estate			116	3,697
Right-of-use assets, finance leases (terminated) obtained in exchange for finance lease liabilities			(70,427)	16,349
Right-of-use assets, finance leases obtained in exchange for assets under capital lease				76,965
Right-of-use assets, operating leases obtained in exchange for operating lease liabilities			33,189	57,165
Capital lease obligation exchanged for finance lease liability				71,111
Other liabilities exchanged for operating lease liabilities				946
Assumption of debt through investments in unconsolidated affiliates				4,688
Debt exchanged for deferred gain on tax credits				(5,262)
Other assets exchanged for deferred gain on tax credits				$ 228
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