CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$ 8,840	$ (2,597)	$ 6,539	$ (9,027)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization			92,807	86,755
Distributions of operating income from unconsolidated affiliates			8,654	12,906
Equity in earnings and gains of unconsolidated affiliates	(1,299)	(376)	(7,129)	(7,079)
Stock compensation expense			7,361	8,332
Amortization of financing costs			5,769	4,350
Impairment charge	321		1,721
Gain on disposition of properties	(12,056)	(5,107)	(14,070)	(5,140)
Deferred gain on tax credits			(5,034)
Other, net			(7,804)	(6,331)
Changes in assets and liabilities:
Other liabilities			(6,071)	(61)
Prepaid expenses and other assets			10,271	(4,860)
Rents receivable			870	(7,452)
Accounts payable and accrued expenses			1,303	(5,210)
Net cash provided by operating activities			95,187	67,183
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of real estate			(256,647)	(104,902)
Development, construction and property improvement costs			(77,636)	(66,238)
Issuance of or advances on notes receivable				(3,002)
Proceeds from the disposition of properties, net			80,120	52,759
Investments in and advances to unconsolidated affiliates and other			(154,256)	(3,481)
Return of capital from unconsolidated affiliates and other			38,359	23,777
Proceeds from notes receivable			15,250	26,000
Return of deposits for properties under contract			1,060	1,750
Payment of deferred leasing costs			(5,874)	(2,981)
Net cash used in investing activities			(359,624)	(76,318)
CASH FLOWS FROM FINANCING ACTIVITIES
Principal payments on mortgage and other notes			(166,865)	(69,050)
Principal payments on unsecured debt			(352,195)	(578,600)
Proceeds received on mortgage and other notes			183,556	122,332
Proceeds from unsecured debt			444,575	578,800
Payments for repurchase of Common Shares				(55,057)
Payments of finance lease obligations			(2,125)
Proceeds from the sale of Common Stock, net			135,750
Capital contributions from noncontrolling interests			161,628	46,990
Distributions to noncontrolling interests			(39,917)	(29,731)
Dividends paid to Common Shareholders			(69,641)	(66,869)
Deferred financing and other costs			(4,170)	(3,316)
Net cash provided by (used in) financing activities			290,596	(54,501)
Increase (decrease) in cash and restricted cash			26,159	(63,636)
Cash of $21,268 and $74,823 and restricted cash of $13,580 and $10,846, respectively, beginning of period			34,848	85,669	$ 85,669
Cash of $48,140 and $9,525 and restricted cash of $12,867 and $12,508, respectively, end of period	$ 61,007	$ 22,033	61,007	22,033	$ 34,848
Supplemental disclosure of cash flow information
Cash paid during the period for interest, net of capitalized interest of $8,430 and $4,366 respectively			53,586	45,251
Cash paid for income taxes, net of refunds			730	1,227
Supplemental disclosure of non-cash investing and financing activities
Assumption of accounts payable and accrued expenses through acquisition of real estate			3,697	1,014
Right-of-use assets, finance leases obtained in exchange for finance lease liabilities			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			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
Acquisition of undivided interest in a property through conversion of notes receivable				$ 22,201
Debt exchanged for deferred gain on tax credits			(5,262)
Other assets exchanged for deferred gain on tax credits			$ 228