Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Operating Activities
Net income	$ 58,416	$ 66,936
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	95,760	77,070
Loss on early extinguishment of debt	2,225	3,743
Gain on sale of land parcel	(1,864)
Gain on sale of real estate	(2)
Amortization of loan fees and costs	4,857	4,605
Amortization of debt premiums/discounts	289	2,504
Amortization of acquired above and below market leases	(1,578)	(7,580)
Deferred rent	(13,991)	(9,592)
Stock compensation expense	6,567	5,105
Equity in loss related to investments	26
Gain on sales of investments	(11,126)	(2,579)
Loss on sales of investments	1,089	1,768
Changes in operating assets and liabilities:
Restricted cash	(610)	110
Tenant receivables	1,366	1,005
Deferred leasing costs	(13,791)	(40,424)
Other assets	(9,331)	8,539
Accounts payable, accrued expenses, and tenant security deposits	24,318	(982)
Net cash provided by operating activities	142,620	110,228
Investing Activities
Proceeds from sale of property	1,905
Additions to properties	(258,573)	(161,762)
Purchase of properties	(42,171)	(307,839)
Change in restricted cash related to construction projects	(11,532)	(4)
Distributions from unconsolidated real estate entity	22,250
Contributions to unconsolidated real estate entity	(4,918)	(2,038)
Additions to investments	(16,344)	(12,721)
Proceeds from investments	17,559	8,581
Net cash used in investing activities	(291,824)	(475,783)
Financing Activities
Principal reductions of secured notes payable	(4,525)	(16,297)
Proceeds from issuance of unsecured senior notes payable	544,649
Repurchase of unsecured senior convertible notes	(84,801)	(98,590)
Principal borrowings from unsecured senior line of credit and unsecured senior bank term loan	529,147	1,708,317
Repayments of borrowings from unsecured senior line of credit	(520,147)	(1,631,317)
Repayment of unsecured senior bank term loan	(250,000)
Redemption of Series C Preferred Stock	(129,638)
Proceeds from issuance of Series E Preferred Stock	124,868
Proceeds from issuance of common stock	37,385	451,538
Change in restricted cash related to financings	(7,714)	4,824
Deferred financing costs paid	(15,739)	(18,126)
Proceeds from exercise of stock options	155	1,165
Dividends paid on common stock	(60,791)	(49,896)
Dividends paid on preferred stock	(14,178)	(14,178)
Distributions to redeemable noncontrolling interests	(630)	(622)
Contributions by noncontrolling interests	1,125
Distributions to noncontrolling interests	(598)	(1,468)
Net cash provided by financing activities	148,568	335,350
Effect of exchange rate changes on cash and cash equivalents	3,034	(102)
Net increase (decrease) in cash and cash equivalents	2,398	(30,307)
Cash and cash equivalents at beginning of period	78,539	91,232
Cash and cash equivalents at end of period	80,937	60,925
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	$ 23,154	$ 25,992