Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Consolidated net income	$ 86,618	$ 31,286
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	97,691	87,475
Stock compensation expense	1,730	4,445
Redeemable stock issued	428	397
Amortization of debt premium	(541)	(270)
Loss from investments in real estate joint ventures	170	530
Gain on debt extinguishment	(5)	111
Derivative interest expense	590	407
Loss on sale of non-depreciable assets	45	(6)
Gain on sale of discontinued operations	(38,474)	(4,927)
Net casualty loss and other settlement proceeds	(19)	692
Changes in assets and liabilities:
Restricted cash	63	(669)
Other assets	(4,569)	(3,276)
Accounts payable	3,572	1,262
Accrued expenses and other	10,040	12,007
Security deposits	445	(265)
Net cash provided by operating activities	158,021	129,211
Cash flows from investing activities:
Purchases of real estate and other assets	(314,909)	(261,948)
Improvements to existing real estate assets	(36,989)	(34,508)
Construction capital and other improvements	(2,561)	(3,927)
Renovations to existing real estate assets	(11,070)	(9,586)
Development	(54,242)	(21,921)
Distributions from real estate joint ventures	11,880	1,158
Contributions to real estate joint ventures	(204)	(1,387)
Proceeds from disposition of real estate assets	97,113	10,934
Net cash used in investing activities	(310,982)	(321,185)
Cash flows from financing activities:
Net change in credit lines	(235,064)	(95,000)
Proceeds from notes payable	271,000	285,350
Principal payments on notes payable	(11,760)	(102,384)
Funding of escrow for future principal payments on notes payable	0	(10,763)
Payment of deferred financing costs	(3,577)	(2,650)
Repurchase of common stock	(1,863)	(2,471)
Proceeds from issuances of common shares	173,960	170,515
Distributions to noncontrolling interests	(3,775)	(3,980)
Dividends paid on common shares	(79,855)	(68,331)
Net cash (used in) provided by financing activities	109,066	170,286
Net (decrease) increase in cash and cash equivalents	(43,895)	(21,688)
Cash and cash equivalents, beginning of period	57,317	45,942
Cash and cash equivalents, end of period	13,422	24,254
Supplemental disclosure of cash flow information:
Interest paid	47,735	43,230
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	2,672	3,004
Accrued construction in progress	6,392	8,864
Interest capitalized	1,844	720
Marked-to-market adjustment on derivative instruments	6,521	7,120
Reclassification of redeemable stock to liabilities	0	152
Fair value adjustment on debt assumed	2,578	0
Notes Assumed	30,290	0
Segment, Continuing Operations [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on debt extinguishment	$ 322