Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS
Land and improvements	$ 1,202,872	$ 1,166,409
Buildings and tenant improvements	4,766,793	5,396,339
Construction in progress	44,259	61,205
Investments in and advances to unconsolidated companies	364,859	367,445
Undeveloped land	622,635	625,353
Real estate investment property, at cost, total	7,001,418	7,616,751
Accumulated depreciation	(1,108,650)	(1,290,417)
Net real estate investments	5,892,768	6,326,334
Real estate investments and related assets held-for-sale	55,580	394,287
Cash and cash equivalents	213,809	18,384
Accounts receivable, net of allowance of $3,597 and $2,945	22,255	22,588
Straight-line rent receivable, net of allowance of $7,447 and $7,260	105,900	125,185
Receivables on construction contracts, including retentions	40,247	7,408
Deferred financing costs, net of accumulated amortization of $59,109 and $46,407	42,268	46,320
Deferred leasing and other costs, net of accumulated amortization of $292,334 and $269,000	460,881	517,934
Escrow deposits and other assets	170,729	185,836
Assets, total	7,004,437	7,644,276
LIABILITIES AND EQUITY
Secured debt	1,173,233	1,065,628
Unsecured notes	2,616,063	2,948,405
Unsecured lines of credit	20,293	193,046
Long-term debt, total	3,809,589	4,207,079
Liabilities related to real estate investments held-for-sale	975	14,732
Construction payables and amounts due subcontractors, including retentions	55,775	44,782
Accrued real estate taxes	69,272	83,615
Accrued interest	58,904	62,407
Other accrued expenses	60,174	61,448
Other liabilities	131,735	129,860
Tenant security deposits and prepaid rents	38,355	50,450
Total liabilities	4,224,779	4,654,373
Shareholders' equity:
Preferred shares ($.01 par value); 5,000 shares authorized; 3,176 and 3,618 shares issued and outstanding	793,910	904,540
Common shares ($.01 par value); 400,000 shares authorized; 252,927 and 252,195 shares issued and outstanding	2,529	2,522
Additional paid-in capital	3,594,588	3,573,720
Accumulated other comprehensive income (loss)	987	(1,432)
Distributions in excess of net income	(1,677,328)	(1,533,740)
Total shareholders' equity	2,714,686	2,945,610
Noncontrolling interests	64,972	44,293
Total equity	2,779,658	2,989,903
Liabilities and stockholders' equity, total	$ 7,004,437	$ 7,644,276