CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]
Net cash provided by operating activities:	$ 165,547	$ 155,084
Cash flows from investing activities:
Acquisition of real estate, including intangible assets	(51,962)	(81,535)
Investment in real estate under construction	(106,502)	(79,381)
Capital expenditures	(9,434)	(38,067)
Net proceeds from sale of properties	85,115	69,387
Principal payments received on loans receivable	11,496	1,666
Investment in loans receivable	(40,248)	(21,121)
Investments in non-consolidated entities	0	(5,000)
Distributions from non-consolidated entities in excess of accumulated earnings	879	15,460
Increase in deferred leasing costs	(8,414)	(9,957)
Change in escrow deposits and restricted cash	(42,579)	(8,571)
Real estate deposits, net	1,332	(16,078)
Net cash used in investing activities	(160,317)	(173,197)
Cash flows from financing activities:
Dividends to common and preferred shareholders	(118,840)	(101,724)
Conversion of convertible notes	(62)	(3,270)
Principal amortization payments	(28,303)	(28,953)
Principal payments on debt, excluding normal amortization	(163,267)	(347,122)
Change in credit facility borrowings, net	(48,000)	67,000
Proceeds from senior notes	249,708	247,565
Proceeds from term loans	99,000	64,000
Increase in deferred financing costs	(3,402)	(7,386)
Proceeds of mortgages and notes payable	27,790	40,000
Cash distributions to noncontrolling interests	(2,881)	(2,903)
Redemption of noncontrolling interests	(1,962)	0
Purchase of noncontrolling interests	(2,100)	(8,918)
Repurchase of preferred shares	0	(155,004)
Issuance of common shares, net	19,165	306,986
Net cash provided by financing activities	26,846	70,271
Change in cash and cash equivalents	32,076	52,158
Cash and cash equivalents, at beginning of period	77,261	34,024
Cash and cash equivalents, at end of period	$ 109,337	$ 86,182