Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
OPERATING ACTIVITIES
Net income (loss)	$ 6,062	$ (3,751)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
Depreciation and amortization	49,762	43,919
Stock-based compensation	1,653	1,602
Straight-line rent receivable	(3,445)	(2,395)
Straight-line rent liability	202	246
Gain on sales of real estate properties	(3,431)	(36)
Loss on extinguishment of debt	0	1,986
Impairments	4,336	147
Provision for bad debt, net	108	287
Changes in operating assets and liabilities:
Other assets	4,050	(5,376)
Accounts payable and accrued liabilities	(9,573)	2,649
Other liabilities	3,073	7,217
Net cash provided by operating activities	52,797	46,495
INVESTING ACTIVITIES
Acquisition and development of real estate properties	(61,522)	(83,111)
Funding of mortgages and notes receivable	(28,550)	(83,141)
Proceeds from sales of real estate	36,109	3,775
Proceeds from mortgage repayment by consolidated variable interest entity	35,057	0
Proceeds from mortgages and notes receivable repayments	9,232	58
Net cash used in investing activities	(9,674)	(162,419)
FINANCING ACTIVITIES
Net borrowings on unsecured credit facility	4,000	123,000
Repayments on notes and bonds payable	(2,436)	(1,616)
Repurchase of notes payable	0	(280,201)
Dividends paid	(46,785)	(42,570)
Proceeds from issuance of common stock	511	224,045
Common stock redemptions	(45)	(51)
Distributions to noncontrolling interest holders	0	(281)
Purchase of noncontrolling interests	0	(1,591)
Debt issuance costs	(3)	(356)
Net cash provided by (used in) financing activities	(44,758)	20,379
Increase (decrease) in cash and cash equivalents	(1,635)	(95,545)
Cash and cash equivalents, beginning of period	4,738	113,321
Cash and cash equivalents, end of period	3,103	17,776
Supplemental Cash Flow Information:
Interest paid	38,307	33,437
Capitalized interest	3,469	4,194
Company-financed real estate property sales	11,200	2,700
Invoices accrued for construction, tenant improvement and other capitalized costs	5,931	15,001
Construction liabilities transferred upon deconsolidation of variable interest entity	$ 3,450	$ 0