Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating Activities
Net income	$ 96,027	$ 76,721
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	142,677	143,933
Loss on early extinguishment of debt	1,992	2,225
Gain on sale of land parcel	(772)	(1,864)
Loss (gain) on sale of real estate	121	(1,564)
Non-cash impairment of real estate	0	9,799
Amortization of loan fees and costs	7,300	7,327
Amortization of debt premiums/discounts	383	401
Amortization of acquired above and below market leases	(2,490)	(2,356)
Deferred rent	(20,007)	(19,216)
Stock compensation expense	11,541	10,412
Equity in loss related to investments	0	26
Gain on sales of investments	(4,716)	(12,316)
Loss on sales of investments	529	1,607
Changes in operating assets and liabilities:
Restricted cash	1,243	441
Tenant receivables	(271)	(2,637)
Deferred leasing costs	(37,190)	(23,597)
Other assets	(11,428)	(3,230)
Accounts payable, accrued expenses, and tenant security deposits	51,437	41,378
Net cash provided by operating activities	236,376	227,490
Investing Activities
Proceeds from sale of properties	101,815	36,179
Additions to properties	(450,140)	(406,066)
Purchase of properties	(24,537)	(42,171)
Change in restricted cash related to construction projects	5,711	(11,453)
Distribution from unconsolidated real estate entity	0	22,250
Contributions to unconsolidated real estate entity	(13,881)	(5,042)
Additions to investments	(22,835)	(21,997)
Proceeds from investments	12,750	19,905
Net cash used in investing activities	(391,117)	(408,395)
Financing Activities
Borrowings from secured notes payable	26,319	2,874
Repayments of borrowings from secured notes payable	(34,120)	(8,125)
Proceeds from issuance of unsecured senior notes payable	498,561	549,533
Principal borrowings from unsecured senior line of credit and unsecured senior bank term loans	319,000	623,147
Repayments of borrowings from unsecured senior line of credit	(871,000)	(580,147)
Repayment of unsecured senior bank term loan	(250,000)	(250,000)
Repurchase of unsecured senior convertible notes	(384)	(84,801)
Redemption of Series C Cumulative Redeemable Preferred Stock	0	(129,638)
Proceeds from issuance of Series E Cumulative Redeemable Preferred Stock	0	124,868
Change in restricted cash related to financings	923	(10,476)
Deferred financing costs paid	(16,247)	(25,301)
Proceeds from common stock offering	535,686	98,443
Proceeds from exercise of stock options	0	155
Dividends paid on common stock	(120,367)	(92,743)
Dividends paid on preferred stock	(19,414)	(21,348)
Distributions to redeemable noncontrolling interests	0	(943)
Redemption of redeemable noncontrolling interests	0	(150)
Contributions by noncontrolling interests	0	1,626
Distributions to noncontrolling interests	(2,100)	(770)
Net cash provided by financing activities	66,857	196,204
Effect of foreign exchange rate changes on cash and cash equivalents	752	1,066
Net increase (decrease) in cash and cash equivalents	(87,132)	16,365
Cash and cash equivalents at beginning of period	140,971	78,539
Cash and cash equivalents at end of period	53,839	94,904
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest, net of interest capitalized	34,281	30,485
Non-Cash Investing Activities
Note receivable from sale of real estate	$ 38,820	$ 6,125