Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
OPERATING ACTIVITIES
Net income (loss)	$ (3,751)	$ 11,173
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation and amortization	43,919	37,924
Stock-based compensation	1,602	1,320
Straight-line rent receivable	(2,395)	(1,319)
Straight-line rent liability	246	206
Gain on sales of real estate properties	(36)	(4,221)
Loss on extinguishment of debt	1,986	480
Impairment	147
Provision for bad debt, net	287	(457)
Payment of partial pension settlement		(342)
Changes in operating assets and liabilities:
Other assets	(5,376)	(162)
Accounts payable and accrued liabilities	2,649	5,187
Other liabilities	7,217	(248)
Net cash provided by operating activities	46,495	49,541
INVESTING ACTIVITIES
Acquisition and development of real estate properties	(83,111)	(54,057)
Funding of mortgages and notes receivable	(83,141)	(2,890)
Proceeds from sales of real estate	3,775	23,623
Proceeds from mortgages and notes receivable repayments	58	69
Net cash used in investing activities	(162,419)	(33,255)
FINANCING ACTIVITIES
Net borrowings (repayments) on unsecured credit facility	123,000	(30,000)
Repayments on notes and bonds payable	(1,616)	(1,111)
Repurchase of notes payable	(280,201)	(8,556)
Dividends paid	(42,570)	(37,370)
Proceeds from issuance of common stock	224,045	59,449
Common stock redemptions	(51)
Capital contributions received from noncontrolling interests		670
Distributions to noncontrolling interest holders	(281)	(249)
Purchase of noncontrolling interests	(1,591)
Debt issuance costs	(356)	(515)
Net cash provided by (used in) financing activities	20,379	(17,682)
Decrease in cash and cash equivalents	(95,545)	(1,396)
Cash and cash equivalents, beginning of year	113,321	5,851
Cash and cash equivalents, end of year	17,776	4,455
Supplemental Cash Flow Information:
Interest paid	33,437	24,458
Capitalized interest	4,194	5,050
Company-financed real estate property sales	2,700
Invoices accrued for construction, tenant improvement and other capitalized costs	$ 15,001	$ 9,913