Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
OPERATING ACTIVITIES
Net income	$ 156,232	$ 149,612	$ 128,237
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization, including discontinued operations	142,039	126,568	119,817
Litigation provision	0	0	(250)
Gain on sale of real estate	(11,860)	(15,075)	(1,410)
Gain on deconsolidation of VIE	0	(2,026)	0
Early extinguishment of debt	0	(296)	2,801
Income from real estate partnerships	(1,757)	(1,808)	(1,060)
Other, net	4,348	3,871	4,099
Changes in assets and liabilities, net of effects of acquisitions and dispositions
Increase in accounts receivable	7,332	1,888	7,461
(Increase) decrease in prepaid expenses and other assets	(7,793)	2,613	(2,824)
Increase (decrease) in accounts payable and accrued expenses	3,259	(14,994)	(879)
Increase (decrease) in security deposits and other liabilities	4,833	(5,642)	743
Net cash provided by operating activities	296,633	244,711	256,735
INVESTING ACTIVITIES
Acquisition of real estate	(80,865)	(103,557)	(57,133)
Capital expenditures - development and redevelopment	(129,346)	(91,922)	(50,414)
Capital expenditures - other	(51,325)	(50,540)	(38,681)
Proceeds from sale of real estate	0	23,695	0
Investment in real estate partnerships	0	(6,947)	(16,930)
Distribution from real estate partnership in excess of earnings	1,116	1,070	237
Distribution from sale of real estate partnership properties	0	34,617	0
Leasing costs	(14,233)	(12,415)	(10,272)
Repayment of mortgage and other notes receivable, net	1,095	9,630	(13,895)
Net cash used in investing activities	(273,558)	(196,369)	(187,088)
FINANCING ACTIVITIES
Net (repayments) borrowings under revolving credit facility, net of costs	0	(81,159)	76,550
Issuance of senior notes, net of costs	244,807	0	148,457
Purchase and retirement of senior notes/debentures	(175,000)	(75,000)	0
Issuance of mortgages, capital leases and notes payable, net of costs	5,399	272,193	9,950
Repayment of mortgages, capital leases and notes payable	(53,414)	(91,952)	(262,340)
Issuance of common shares	114,134	156,862	6,610
Dividends paid to common and preferred shareholders	(179,884)	(169,254)	(163,120)
Distributions to and redemptions of noncontrolling interests	(9,935)	(8,023)	(5,346)
Net cash (used in) provided by financing activities	(53,893)	3,667	(189,239)
(Decrease) increase in cash and cash equivalents	(30,818)	52,009	(119,592)
Cash and cash equivalents at beginning of year	67,806	15,797	135,389
Cash and cash equivalents at end of period	$ 36,988	$ 67,806	$ 15,797