CONSOLIDATED STATEMENTS OF EQUITY AND COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands	Total	Series A Preferred Stock [Member]	Series B Preferred Stock [Member]	Preferred Stock [Member] Series A Preferred Stock [Member]	Preferred Stock [Member] Series B Preferred Stock [Member]	Common Shares [Member] Common Class A [Member]	Common Shares [Member] Common Class B [Member]	Additional Paid-in Capital [Member]	Other Comprehensive Income [Member]	Distributions in Excess of Net Earnings [Member]	Distributions in Excess of Net Earnings [Member] Series A Preferred Stock [Member]	Distributions in Excess of Net Earnings [Member] Series B Preferred Stock [Member]	Total Shareholders' Equity [Member]	Total Shareholders' Equity [Member] Series A Preferred Stock [Member]	Total Shareholders' Equity [Member] Series B Preferred Stock [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] Corporate Joint Venture [Member]	Noncontrolling Interest [Member] Common Units [Member]	Redeemable Noncontrolling Interests [Member] Common Units [Member]
Balance, redeemable noncontrolling interests at Dec. 31, 2009																			$ 14,733
Balance at Dec. 31, 2009	329,590							487,481	(160)	(185,725)			302,197			27,393	267	27,126
Balance (in shares) at Dec. 31, 2009				24	0	577	0
Unit Conversion (in shares)				0	0	23	0
Unit Conversion	0							10,203	0	0			10,226			(10,226)	0	(10,226)
Reallocation of Noncontrolling Interest	(1,813)			0	0	0	0	(1,813)	0				(1,813)
Reallocation of Noncontrolling Interest, redeemable noncontrolling interest																			1,813
Units Issued for Acquisitions	6,256			0	0	0	0	0	0	0			0			6,256	0	6,256
Share Offering or Issuance (in shares)				0	0	794	0
Share Offering or Issuance, net of costs	260,764							259,970	0	0			260,764			0	0	0
Dividends and Distributions declared:
Common Stock	(20,816)			0	0	0	0	0	0	(20,816)			(20,816)			0	0	0
Preferred Stock		(3,600)		0	0	0	0	0	0		(3,600)			(3,600)		0	0	0
Common Units	(869)			0	0	0	0	0	0	0			0			(869)	0	(869)
Common Units, redeemable noncontrolling interest																			(461)
Dividend Reinvestment Plan	9			0	0	0	0	9	0	0			9			0	0	0
Grants (in shares)				0	0	4	0
Grants	570							566	0	0			570			0	0	0
Amortization	3,317			0	0	0	0	3,317	0	0			3,317			0	0	0
Comprehensive Income (Loss):
Other Comprehensive Income (Loss)	(264)			0	0	0	0	0	(264)	0			(264)			0	0	0
Net Loss	(8,815)			0	0	0	0	0	0	(8,726)			(8,726)			(89)	325	(414)
Net Loss, redeemable noncontrolling interest																			(213)
Total Comprehensive Loss	(9,079)												(8,990)			(89)	325	(414)
Total Comprehensive Loss, redeemable noncontrolling interest																			(213)
Balance, redeemable noncontrolling interests at Sep. 30, 2010																			15,872
Balance at Sep. 30, 2010	564,329							759,733	(424)	(218,867)			541,864			22,465	592	21,873
Balance (in shares) at Sep. 30, 2010				24	0	1,398	0
Balance, redeemable noncontrolling interests at Dec. 31, 2010																			19,894
Balance at Dec. 31, 2010	703,318							918,215	(338)	(236,159)			683,434			19,884	474	19,410
Balance (in shares) at Dec. 31, 2010				24	0	1,692	0
Unit Conversion (in shares)				0	0	2	0
Unit Conversion	(229)							637	0	0			639			(868)	0	(868)
Unit Conversion, redeemable noncontrolling interest																			229
Reallocation of Noncontrolling Interest	6,374			0	0	0	0	6,387	0	0			6,387			(13)	0	(13)
Reallocation of Noncontrolling Interest, redeemable noncontrolling interest																			(6,374)
Share Offering or Issuance (in shares)				0	46	0	0
Share Offering or Issuance, net of costs	110,997							110,951	0	0			110,997			0	0	0
Dividends and Distributions declared:
Common Stock	(28,881)			0	0	0	0	0	0	(28,881)			(28,881)			0	0	0
Preferred Stock		(3,600)	(3,399)	0	0	0	0	0	0		(3,600)	(3,399)		(3,600)	(3,399)	0	0	0
Common Units	(718)			0	0	0	0	0	0	0			0			(718)	0	(718)
Common Units, redeemable noncontrolling interest																			(518)
Contribution by Noncontrolling Interests in consolidated joint venture	342			0	0	0	0	0	0	0			0			342	342	0
Deconsolidation of consolidated joint venture	(322)			0	0	0	0	0	0	0			0			(322)	(322)
Dividend Reinvestment Plan	11			0	0	0	0	11	0	0			11			0	0	0
Grants (in shares)				0	0	5	0
Grants	1,476							1,471	0	0			1,476			0	0	0
Amortization	4,376			0	0	0	0	4,376	0	0			4,376			0	0	0
Comprehensive Income (Loss):
Other Comprehensive Income (Loss)	(909)			0	0	0	0	0	(909)	0			(909)			0	0	0
Net Loss	(26,981)			0	0	0	0	0	0	(25,955)			(25,955)			(1,026)	(192)	(834)
Net Loss, redeemable noncontrolling interest																			(593)
Total Comprehensive Loss	(27,890)												(26,864)			(1,026)	(192)	(834)
Total Comprehensive Loss, redeemable noncontrolling interest																			(593)
Balance, redeemable noncontrolling interests at Sep. 30, 2011																			12,638
Balance at Sep. 30, 2011	$ 761,855							$ 1,042,048	$ (1,247)	$ (297,994)			$ 744,576			$ 17,279	$ 302	$ 16,977
Balance (in shares) at Sep. 30, 2011				24	46	1,699	0