CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Statement of Cash Flows [Abstract]
Net cash provided by operating activities:	$ 112,509	$ 103,721
Cash flows from investing activities:
Acquisition of real estate, including intangible assets	(197,926)	(51,962)
Investment in real estate under construction	(62,290)	(69,073)
Capital expenditures	(5,343)	(5,403)
Net proceeds from sale of properties	78,857	33,226
Principal payments received on loans receivable	1,130	1,104
Investment in loans receivable	(9,857)	(20,833)
Investments in non-consolidated entities	(10,005)	0
Distributions from non-consolidated entities in excess of accumulated earnings	896	876
Increase in deferred leasing costs	(3,176)	(6,519)
Change in escrow deposits and restricted cash	1,507	(2,610)
Real estate deposits, net	(5,944)	(37)
Net cash used in investing activities	(212,151)	(121,231)
Cash flows from financing activities:
Dividends to common and preferred shareholders	(82,192)	(78,343)
Conversion of convertible notes	0	(62)
Principal amortization payments	(20,138)	(20,971)
Principal payments on debt, excluding normal amortization	106,956	163,267
Change in credit facility borrowings, net	93,000	(48,000)
Proceeds from senior notes	0	249,708
Proceeds from term loans	0	99,000
Increase in deferred financing costs	(2,695)	(3,215)
Proceeds of mortgages and notes payable	80,843	27,790
Cash distributions to noncontrolling interests	(1,871)	(2,186)
Redemption of noncontrolling interests	0	(1,962)
Issuance of common shares, net	12,956	10,861
Net cash provided by (used in) financing activities	(27,053)	69,353
Change in cash and cash equivalents	(126,695)	51,843
Cash and cash equivalents, at beginning of period	191,077	77,261
Cash and cash equivalents, at end of period	$ 64,382	$ 129,104