CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Statement of Cash Flows [Abstract]
Net cash provided by operating activities:	$ 57,921	$ 59,942
Cash flows from investing activities:
Acquisition of real estate, including intangible assets	(197,275)	(38,643)
Investment in real estate under construction	(30,778)	(46,376)
Capital expenditures	(1,717)	(3,051)
Net proceeds from sale of properties	4,433	325
Principal payments received on loans receivable	64	401
Investment in loans receivable	(83)	(20,267)
Investments in non-consolidated entity	(3,032)	0
Distributions from non-consolidated entities in excess of accumulated earnings	221	315
Increase in deferred leasing costs	(1,420)	(3,985)
Change in escrow deposits and restricted cash	(1,540)	(801)
Real estate deposits, net	(1,999)	(308)
Net cash used in investing activities	(233,126)	(112,390)
Cash flows from financing activities:
Dividends to common and preferred shareholders	(41,045)	(39,098)
Conversion of convertible notes	0	(62)
Principal amortization payments	(13,867)	(14,139)
Principal payments on debt, excluding normal amortization	(83,320)	(19,515)
Change in credit facility borrowings, net	93,000	(6,000)
Proceeds from term loans	0	99,000
Increase in deferred financing costs	(2,444)	(482)
Proceeds of mortgages and notes payable	80,843	0
Cash distributions to noncontrolling interests	(800)	(938)
Redemption of noncontrolling interests	0	(1,962)
Issuance of common shares, net	6,582	4,433
Net cash provided by financing activities	38,949	21,237
Change in cash and cash equivalents	(136,256)	(31,211)
Cash and cash equivalents, at beginning of period	191,077	77,261
Cash and cash equivalents, at end of period	$ 54,821	$ 46,050