Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Consolidated net income	$ 25,068	$ 9,155
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	31,549	28,456
Stock compensation expense	814	844
Redeemable stock issued	116	97
Amortization of debt premium	(90)	(90)
Loss from investments in real estate joint ventures	31	245
Gain on debt extinguishment	(20)	0
Derivative interest expense	164	47
Loss on sale of non-depreciable assets	0	6
Gain on sale of discontinued operations	(9,500)	0
Net casualty loss and other settlement proceeds	58	148
Changes in assets and liabilities:
Restricted cash	207	137
Other assets	2,445	(1,470)
Accounts payable	1,910	789
Accrued expenses and other	(14,994)	(6,922)
Security deposits	82	(140)
Net cash provided by operating activities	37,840	31,302
Cash flows from investing activities:
Purchases of real estate and other assets	0	(30,000)
Improvements to existing real estate assets	(12,221)	(10,295)
Renovations to existing real estate assets	(2,934)	(2,416)
Development	(26,745)	(3,569)
Distributions from real estate joint ventures	459	362
Contributions to real estate joint ventures	(51)	(1,369)
Proceeds from disposition of real estate assets	29,035	0
Funding of escrow for future acquisitions	(21,585)	0
Net cash used in investing activities	(34,042)	(47,287)
Cash flows from financing activities:
Net change in credit lines	(158,802)	(70,000)
Proceeds from notes payable	50,000	22,350
Principal payments on notes payable	(807)	(671)
Payment of deferred financing costs	(1,397)	(420)
Repurchase of common stock	(1,415)	(1,939)
Proceeds from issuances of common shares	120,135	91,443
Distributions to noncontrolling interests	(1,280)	(1,422)
Dividends paid on common shares	(25,723)	(22,076)
Net cash (used in) provided by financing activities	(19,289)	17,265
Net (decrease) increase in cash and cash equivalents	(15,491)	1,280
Cash and cash equivalents, beginning of period	57,317	45,942
Cash and cash equivalents, end of period	41,826	47,222
Supplemental disclosure of cash flow information:
Interest paid	16,911	13,518
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	28	2,071
Accrued construction in progress	10,027	7,467
Interest capitalized	638	167
Marked-to-market adjustment on derivative instruments	4,084	7,414
Reclassification of redeemable stock to liabilities	$ 0	$ 151