CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Cash Flows [Abstract]
Net cash provided by operating activities:	$ 59,942	$ 57,132
Cash flows from investing activities:
Acquisition of real estate, including intangible assets	(38,643)	(81,535)
Investment in real estate under construction	(46,376)	(18,047)
Capital expenditures	(3,051)	(17,372)
Net proceeds from sale of properties	325	1,861
Principal payments received on loans receivable	401	716
Investment in loans receivable	(20,267)	(10,596)
Distributions from non-consolidated entities in excess of accumulated earnings	315	14,975
Increase in deferred leasing costs	(3,985)	(2,794)
Change in escrow deposits and restricted cash	(801)	308
Real estate deposits	(308)	(192)
Net cash used in investing activities	(112,390)	(112,676)
Cash flows from financing activities:
Dividends to common and preferred shareholders	(39,098)	(31,285)
Conversion of convertible notes	(62)	(2,663)
Principal amortization payments	(14,139)	(18,733)
Principal payments on debt, excluding normal amortization	(19,515)	(147,291)
Change in credit facility borrowings, net	(6,000)	0
Proceeds from term loans	99,000	0
Increase in deferred financing costs	(482)	(4,025)
Proceeds of mortgages and notes payable	0	40,000
Cash distributions to noncontrolling interests	(938)	(902)
Purchase of noncontrolling interests	1,962	0
Issuance of common shares, net	4,433	297,823
Net cash provided by financing activities	21,237	132,924
Change in cash and cash equivalents	(31,211)	77,380
Cash and cash equivalents, at beginning of period	77,261	34,024
Cash and cash equivalents, at end of period	$ 46,050	$ 111,404