Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities:
Net Income	$ 322,575	$ 345,343	$ 350,715
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	135,674	161,838	167,101
Amortization of debt deferred costs and intangibles, net	3,194	3,146	2,790
Non-cash lease expense	1,241	0	0
Impairment loss	74	10,120	15,257
Equity in earnings of real estate joint ventures and partnerships, net	(20,769)	(25,070)	(27,074)
Gain on sale of property	(189,914)	(207,865)	(218,611)
Distributions of income from real estate joint ventures and partnerships	20,083	19,605	1,321
Changes in accrued rent, accrued contract receivables and accounts receivable, net	10,001	(2,807)	(18,964)
Changes in unamortized lease costs and other assets, net	(14,298)	(8,632)	(13,299)
Changes in accounts payable, accrued expenses and other liabilities, net	(975)	(2,315)	4,970
Other, net	3,164	(7,403)	5,552
Net cash provided by operating activities	270,050	285,960	269,758
Cash Flows from Investing Activities:
Acquisition of real estate and land, net	(218,849)	(1,265)	(1,902)
Development and capital improvements	(183,188)	(155,528)	(133,336)
Proceeds from sale of property and real estate equity investments, net	445,319	607,486	433,661
Real estate joint ventures and partnerships - Investments	(74,602)	(38,096)	(37,173)
Real estate joint ventures and partnerships - Distributions of capital	2,482	6,936	28,791
Purchase of investments	0	0	(5,730)
Proceeds from investments	10,375	1,500	8,502
Other, net	2,437	11,921	6,179
Net cash (used in) provided by investing activities	(16,026)	432,954	298,992
Cash Flows from Financing Activities:
Proceeds from issuance of debt	0	638	0
Principal payments of debt	(55,556)	(257,028)	(28,723)
Changes in unsecured credit facilities	(5,000)	5,000	(245,000)
Repurchase of common shares of beneficial interest, net	0	(18,564)	0
Proceeds from issuance of common shares of beneficial interest, net	1,098	6,760	1,588
Common share dividends paid	(203,297)	(382,464)	(294,073)
Debt issuance and extinguishment costs paid	(3,271)	(1,271)	(488)
Distributions to noncontrolling interests	(6,782)	(19,155)	(19,342)
Contributions from noncontrolling interests	326	1,465	0
Other, net	(2,388)	508	(2,657)
Net cash used in financing activities	(274,870)	(664,111)	(588,695)
Net (decrease) increase in cash, cash equivalents and restricted cash equivalents	(20,846)	54,803	(19,945)
Cash, cash equivalents and restricted cash equivalents at January 1	76,137	21,334	41,279
Cash, cash equivalents and restricted cash equivalents at December 31	55,291	76,137	21,334
Cash paid for interest (net of amount capitalized of $13,586, $7,938 and $4,868, respectively)	55,413	65,507	79,161
Cash paid for income taxes	1,526	1,545	1,009
Cash paid for amounts included in operating lease liabilities	$ 2,785	$ 0	$ 0