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	$ 23,612	$ 20,502
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization from continuing operations	48,891	46,510
Depreciation and amortization from discontinued operations	0	483
Stock-based compensation expense	3,204	2,781
Gain on sales of land and real estate investments	(24)	(2,036)
Changes in operating assets and liabilities:
Accrued income and other assets	2,202	2,832
Accounts payable, accrued expenses and prepaid rent	10,765	1,977
Other	(71)	134
NET CASH PROVIDED BY OPERATING ACTIVITIES	88,579	73,183
INVESTING ACTIVITIES
Real estate development	(61,561)	(34,834)
Purchases of real estate	(72,397)	(10,950)
Real estate improvements	(16,053)	(13,670)
Proceeds from sales of real estate investments	1,313	7,399
Repayments on mortgage loans receivable	78	3
Changes in accrued development costs	2,062	72
Changes in other assets and other liabilities	(9,411)	(6,429)
NET CASH USED IN INVESTING ACTIVITIES	(155,969)	(58,409)
FINANCING ACTIVITIES
Proceeds from unsecured bank credit facilities	307,725	186,072
Repayments on unsecured bank credit facilities	(272,218)	(294,137)
Proceeds from secured debt	0	54,000
Repayments on secured debt	(51,920)	(68,282)
Proceeds from unsecured debt	100,000	80,000
Debt issuance costs	(1,650)	(1,474)
Distributions paid to stockholders (not including dividends accrued on unvested restricted stock)	(48,252)	(45,035)
Proceeds from common stock offerings	33,490	74,903
Proceeds from exercise of stock options	120	108
Proceeds from dividend reinvestment plan	156	168
Other	(1,112)	(244)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	66,339	(13,921)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(1,051)	853
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	1,258	174
CASH AND CASH EQUIVALENTS AT END OF PERIOD	207	1,027
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for interest, net of amount capitalized of $3,841 and $3,362 for 2013 and 2012, respectively	$ 24,852	$ 26,162