CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $)	Common Stock	Additional Paid-in Capital	Distributions in Excess of Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interest in Joint Ventures	Total
BEGINNING BALANCE at Dec. 31, 2008	$ 3,000	$ 528,452,000	$ (117,093,000)	$ (522,000)	$ 2,536,000	$ 413,376,000
Comprehensive income
Net income	0	0	26,659,000	0	435,000	27,094,000
Net unrealized change in fair value of interest rate swap	0	0	0	204,000	0	204,000
Total comprehensive income	0	0	0	0	0	27,298,000
Common dividends declared - per share	0	0	(53,929,000)	0	0	(53,929,000)
Stock-based compensation, net of forfeitures	0	2,060,000	0	0	0	2,060,000
Stock Issued During Period Value New Issues	0	57,553,000	0	0	0	57,553,000
Issuance of shares of common stock, options exercised	0	1,180,000	0	0	0	1,180,000
Stock Issued During Period Value Dividend Reinvestment Plan	0	268,000	0	0	0	268,000
Withheld shares of common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock	0	(316,000)	0	0	0	(316,000)
Distributions to noncontrolling interest	0	0	0	0	(394,000)	(394,000)
ENDING BALANCE at Dec. 31, 2009	3,000	589,197,000	(144,363,000)	(318,000)	2,577,000	447,096,000
Comprehensive income
Net income	0	0	18,325,000	0	430,000	18,755,000
Net unrealized change in fair value of interest rate swap	0	0	0	318,000	0	318,000
Total comprehensive income	0	0	0	0	0	19,073,000
Common dividends declared - per share	0	0	(56,215,000)	0	0	(56,215,000)
Stock-based compensation, net of forfeitures	0	2,042,000	0	0	0	2,042,000
Issuance of shares of common stock, options exercised	0	404,000	0	0	0	404,000
Stock Issued During Period Value Dividend Reinvestment Plan	0	257,000	0	0	0	257,000
Withheld shares of common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock	0	(794,000)	0	0	0	(794,000)
Distributions to noncontrolling interest	0	0	0	0	(357,000)	(357,000)
ENDING BALANCE at Dec. 31, 2010	3,000	591,106,000	(182,253,000)	0	2,650,000	411,506,000
Comprehensive income
Net income	0	0	22,359,000	0	475,000	22,834,000
Net unrealized change in fair value of interest rate swap						0
Common dividends declared - per share	0	0	(56,666,000)	0	0	(56,666,000)
Stock-based compensation, net of forfeitures	0	2,787,000	0	0	0	2,787,000
Stock Issued During Period Value New Issues	0	25,181,000	0	0	0	25,181,000
Issuance of shares of common stock, options exercised	0	217,000	0	0	0	217,000
Stock Issued During Period Value Dividend Reinvestment Plan	0	252,000	0	0	0	252,000
Withheld shares of common stock to satisfy tax withholding obligations in connection with the vesting of restricted stock	0	(157,000)	0	0	0	(157,000)
Distributions to noncontrolling interest	0	0	0	0	(345,000)	(345,000)
ENDING BALANCE at Dec. 31, 2011	$ 3,000	$ 619,386,000	$ (216,560,000)	$ 0	$ 2,780,000	$ 405,609,000