Consolidated Balance Sheets (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
ASSETS
Land and improvements	$ 1,276,820	$ 1,166,409
Buildings and tenant improvements	5,525,808	5,396,339
Construction in progress	70,424	61,205
Investments in and advances to unconsolidated companies	365,323	367,445
Undeveloped land	617,470	625,353
Real estate investment property, at cost, total	7,855,845	7,616,751
Accumulated depreciation	(1,381,919)	(1,290,417)
Net real estate investments	6,473,926	6,326,334
Real estate investments and other assets held-for-sale		394,287
Cash and cash equivalents	117,645	18,419
Accounts receivable, net of allowance of $3,802 and $2,945	24,741	22,588
Straight-line rent receivable, net of allowance of $7,924 and $7,260	136,171	125,185
Receivables on construction contracts, including retentions	48,263	7,408
Deferred financing costs, net of accumulated amortization of $52,844 and $46,407	42,223	46,317
Deferred leasing and other costs, net of accumulated amortization of $313,986 and $269,000	497,174	517,934
Escrow deposits and other assets	186,562	185,652
Total assets	7,526,705	7,644,124
LIABILITIES AND EQUITY
Secured debt	1,187,044	1,065,628
Unsecured notes	2,906,154	2,948,405
Unsecured lines of credit	18,329	193,046
Total long-term debt	4,111,527	4,207,079
Liabilities related to real estate investments held-for-sale		14,732
Construction payables and amounts due subcontractors, including retentions	67,757	44,782
Accrued real estate taxes	102,695	83,615
Accrued interest	62,046	62,407
Other accrued expenses	38,275	61,354
Other liabilities	136,336	129,860
Tenant security deposits and prepaid rents	53,391	50,450
Total liabilities	4,572,027	4,654,279
Partners' equity:
Common equity (252,663 and 252,195 General Partner Units issued and outstanding)	1,986,945	2,046,617
Preferred equity (3,610 and 3,618 Preferred Units issued and outstanding)	902,540	904,540
Total general partners' equity	2,889,485	2,951,157
Limited Partners' common equity (7,190 and 5,231 Limited Partner Units issued and outstanding)	60,175	34,894
Accumulated other comprehensive income (loss)	56	(1,432)
Total partners' equity	2,949,716	2,984,619
Noncontrolling interests	4,962	5,226
Total equity	2,954,678	2,989,845
Liabilities and partners' capital, total	$ 7,526,705	$ 7,644,124