Condensed Consolidated Statements of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities:
Net income	$ 22,657	$ 13,104
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	27,677	24,621
Amortization of deferred financing costs	2,233	2,347
Non-cash interest expense related to amortization of discount on exchangeable senior notes	868	820
Compensation expense related to stock-based awards	2,711	2,402
Distributions from real estate ventures in excess of earnings	5,169	3,095
Changes in operating assets and liabilities:
Receivables from related parties and affiliated real estate joint ventures	1,393	2,767
Other assets	4,960	(65)
Accounts payable and accrued expenses	(1,498)	(1,193)
Other liabilities	(977)	(1,827)
Net cash provided by operating activities	65,193	46,071
Cash flows from investing activities:
Acquisition of real estate assets	(82,071)	(16,460)
Development and construction of real estate assets	(4,494)	(18,306)
Proceeds from sale of properties to joint venture		15,750
Investments in real estate ventures	(3,405)	(9,059)
Change in restricted cash	(2,202)	5,509
Purchase of equipment and fixtures	(3,463)	(1,115)
Net cash used in investing activities	(95,635)	(23,681)
Cash flows from financing activities:
Proceeds from the sale of common stock	112,532
Proceeds from notes payable and lines of credit	264,686	104,093
Principal payments on notes payable and lines of credit	(335,693)	(210,647)
Deferred financing costs	(3,200)	(1,884)
Redemption of Operating Partnership units held by noncontrolling interest	(271)
Net proceeds from exercise of stock options	10,505	3,705
Dividends paid on common stock	(25,575)	(17,455)
Distributions to noncontrolling interests (Operating Partnership and other)	(4,105)	(3,798)
Net cash provided by (used in) financing activities	18,879	(125,986)
Net decrease in cash and cash equivalents	(11,563)	(103,596)
Cash and cash equivalents, beginning of the period	46,750	131,950
Cash and cash equivalents, end of the period	35,187	28,354
Supplemental schedule of cash flow information
Interest paid, net of amounts capitalized	31,533	31,723
Deconsolidation of joint ventures due to application of Accounting Standards Codification 810:
Real estate assets, net		(42,739)
Investments in real estate ventures		404
Receivables from related parties and affiliated real estate joint ventures		21,142
Other assets and other liabilities		(51)
Notes payable		21,348
Other noncontrolling interests		(104)
Redemption of Operating Partnership units held by noncontrolling interests for common stock	2,344
Acquisitions of real estate assets
Real estate assets, net	8,660	6,475
Notes payable	$ (8,660)	$ (6,475)