CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 1,606,931	$ 448,959	$ 366,389
Adjustments to reconcile net income to net cash provided by operating activities:
Loss (gain) on early extinguishment of debt, net	526	(1,432)	0
(Gain) loss on sale or write down of assets, net	(73,440)	78,057	(28,734)
Gain on remeasurement of assets	(1,423,136)	(51,205)	(199,956)
Gain on disposition of assets, net from discontinued operations	0	(286,414)	(50,811)
Depreciation and amortization	387,785	383,002	322,720
Amortization of net premium on mortgages, bank and other notes payable	(8,906)	(6,822)	(1,600)
Amortization of share and unit-based plans	29,463	24,207	12,324
Straight-line rent adjustment	(5,825)	(7,987)	(6,698)
Amortization of above and below-market leases	(9,083)	(6,726)	(5,405)
Provision for doubtful accounts	3,962	4,150	3,329
Income tax benefit	(4,269)	(1,692)	(4,159)
Equity in income of unconsolidated joint ventures	(60,626)	(167,580)	(79,281)
Co-venture expense	9,490	8,864	6,523
Distributions of income from unconsolidated joint ventures	2,412	8,538	29,147
Changes in assets and liabilities, net of acquisitions and dispositions:
Tenant and other receivables	(12,356)	(5,482)	(2,554)
Other assets	(15,594)	7,761	(17,094)
Due from affiliates	(1,770)	266	(1,181)
Accounts payable and accrued expenses	(123)	(747)	13,430
Other accrued liabilities	(24,735)	(5,682)	(5,093)
Net cash provided by operating activities	400,706	422,035	351,296
Cash flows from investing activities:
Acquisition of properties	(15,233)	(516,239)	(1,061,851)
Development, redevelopment, expansion and renovation of properties	(185,412)	(158,682)	(142,210)
Property improvements	(66,718)	(51,683)	(45,654)
Cash acquired from acquisitions	28,890	0	0
Proceeds from note receivable	4,825	8,347	0
Issuance of notes receivable	(65,130)	(13,330)	(12,500)
Proceeds from maturities of marketable securities	0	23,769	1,378
Deposit on acquisition of property	0	0	(30,000)
Deferred leasing costs	(28,019)	(27,669)	(30,614)
Distributions from unconsolidated joint ventures	78,222	618,048	322,242
Contributions to unconsolidated joint ventures	(336,621)	(97,898)	(95,358)
Collections of loans to unconsolidated joint ventures, net	2,756	589	650
Proceeds from sale of assets	320,123	416,077	136,707
Restricted cash	6,526	70,538	(6,164)
Net cash (used in) provided by investing activities	(255,791)	271,867	(963,374)
Cash flows from financing activities:
Proceeds from mortgages, bank and other notes payable	1,204,946	2,572,764	3,193,451
Payments on mortgages, bank and other notes payable	(853,080)	(3,051,072)	(2,371,890)
Deferred financing costs	(1,267)	(11,966)	(15,108)
Proceeds from share and unit-based plans	1,231	1,188	1,263
Proceeds from stock offerings	0	173,011	177,896
Payment of stock issuance costs	(5,503)	(1,909)	(2,247)
Exercise of stock warrants	0	0	(7,371)
Redemption of noncontrolling interests	(236)	(1,066)	(86)
Contributions from noncontrolling interests	0	4,140	379
Purchase of noncontrolling interest	(55,867)	0	0
Payment of contingent consideration	(18,667)	0	0
Dividends and distributions	(385,725)	(355,506)	(326,185)
Distributions to co-venture partner	(15,555)	(19,564)	(39,479)
Net cash (used in) provided by financing activities	(129,723)	(689,980)	610,623
Net increase (decrease) in cash and cash equivalents	15,192	3,922	(1,455)
Cash and cash equivalents, beginning of year	69,715	65,793	67,248
Cash and cash equivalents, end of year	84,907	69,715	65,793
Supplemental cash flow information:
Cash payments for interest, net of amounts capitalized	186,877	195,129	174,089
Non-cash investing and financing activities:
Accrued development costs included in accounts payable and accrued expenses and other accrued liabilities	83,108	41,334	26,322
Acquisition of property by issuance of common stock	1,166,777	0	30,000
Conversion of Operating Partnership Units to common stock	2,410	12,984	26,991
Acquisition of properties by assumption of mortgage note payable and other accrued liabilities	1,414,659	257,064	420,123
Mortgage notes payable settled in deed-in-lieu of foreclosure	0	84,000	185,000
Mortgage notes payable assumed by buyers in sales of properties	31,725	224,737	0
Note receivable issued in connection with sale of property	9,603	0	0
Acquisition of property in exchange for settlement of notes receivable	14,120	0	0
Acquisition of property in exchange for investment in unconsolidated joint venture	15,767	0	0
Contingent consideration in acquisition of property	10,012	0	0
Assumption of mortgage notes payable and other liabilities from unconsolidated joint ventures	0	54,271	0
Application of deposit to acquire property	$ 0	$ 30,000	$ 0