Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
OPERATING ACTIVITIES
Net income	$ 149,612	$ 128,237	$ 103,872
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization, including discontinued operations	126,568	119,817	115,093
Litigation provision	0	(250)	15,690
Gain on sale of real estate	(15,075)	(1,410)	(1,298)
Gain on deconsolidation of VIE	(2,026)	0	0
Early extinguishment of debt	(296)	2,801	2,639
Income from real estate partnerships	(1,808)	(1,060)	(1,322)
Other, net	3,871	4,099	5,265
Changes in assets and liabilities, net of effects of acquisitions and dispositions
Decrease in accounts receivable	1,888	7,461	7,079
Decrease (increase) in prepaid expenses and other assets	2,613	(2,824)	(716)
(Decrease) increase in accounts payable and accrued expenses	(14,994)	(879)	9,753
(Decrease) increase in security deposits and other liabilities	(5,642)	743	710
Net cash provided by operating activities	244,711	256,735	256,765
INVESTING ACTIVITIES
Acquisition of real estate	(103,557)	(57,133)	(10,531)
Capital expenditures - development and redevelopment	(91,922)	(50,414)	(76,079)
Capital expenditures - other	(50,540)	(38,681)	(26,000)
Proceeds from sale of real estate	23,695	0	2,122
Investment in real estate partnerships	(6,947)	(16,930)	(7,020)
Distribution from real estate partnership in excess of earnings	1,070	237	594
Distribution from sale of real estate partnership properties	34,617	0	0
Leasing costs	(12,415)	(10,272)	(8,924)
Repayment (issuance) of mortgage and other notes receivable, net	9,630	(13,895)	(1,503)
Net cash used in investing activities	(196,369)	(187,088)	(127,341)
FINANCING ACTIVITIES
Net (repayments) borrowings under revolving credit facility, net of costs	(81,159)	76,550	(123,500)
Issuance of senior notes, net of costs	0	148,457	147,534
Purchase and retirement of senior notes/debentures	(75,000)	0	(175,867)
Issuance of mortgages, capital leases and notes payable, net of costs	272,193	9,950	526,617
Repayment of mortgages, capital leases and notes payable	(91,952)	(262,340)	(337,221)
Issuance of common shares	156,862	6,610	115,502
Dividends paid to common and preferred shareholders	(169,254)	(163,120)	(156,100)
Distributions to noncontrolling interests	(8,023)	(5,346)	(6,223)
Net cash used in financing activities	3,667	(189,239)	(9,258)
Increase (decrease) in cash and cash equivalents	52,009	(119,592)	120,166
Cash and cash equivalents at beginning of year	15,797	135,389	15,223
Cash and cash equivalents at end of period	$ 67,806	$ 15,797	$ 135,389