CONSOLIDATED STATEMENTS OF EQUITY AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Shares [Member] Class A [Member]	Common Shares [Member] Class B [Member]	Preferred Shares [Member] Series A Preferred [Member}	Preferred Shares [Member] Series B Preferred [Member}	Additional Paid-In Capital [Member]	Other Comprehensive Income [Member]	Distributions in Excess of Net Earnings [Member]	Total Shareholders' Equity [Member]	Noncontrolling Interests Common Units [Member]	Noncontrolling Interests Consolidated Joint Ventures [Member]	Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests Common Units [Member]
Balance, redeemable noncontrolling interests at Dec. 31, 2008													$ 18,739
Balance at Dec. 31, 2008	386,598	483	0	24		463,772	(109)	(114,207)	349,963	34,781	1,854	36,635
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2008													3,064,252
Balance (in shares) at Dec. 31, 2008		48,276,222	0	2,400,000						5,682,048
Common Stock Issuance	21,342	84	0	0		21,258	0	0	21,342	0	0	0	0
Common Stock Issuance (in shares)		8,442,300	0	0						0			0
Issuance Costs	(1,165)	0	0	0		(1,165)	0	0	(1,165)	0	0	0	0
Unit Conversion	0	0	0	0		255	0	0	255	(255)	0	(255)	0
Unit Conversion (in shares)	44,490	44,490								(44,490)			0
Dividends and Distributions declared:
Common Stock ($0.33, $0.20, and $0.23 per unit)	(16,857)							(16,857)	(16,857)	0	0	0
Distribution to Noncontrolling Interest in Consolidated Joint Ventures	(124)	0	0	0		0	0	0	0	0	(124)	(124)	0
Common Units ($0.33, $0.20, and $0.23 per unit)	(1,871)	0	0	0		0	0			(1,871)	0	(1,871)	(1,010)
Preferred Stock, Series A	(4,800)	0	0	0		0	0	(4,800)	(4,800)	0	0	0	0
Dividend Reinvestment Plan	25	0	0	0		25	0	0	25	0	0	0	0
Dividend Reinvestment Plan (in shares)		9,943	0	0						0			0
Restricted and Performance Share Award Grants	0	9	0	0		(9)	0	0	0	0	0	0	0
Restricted and Performance Share Award Grants (in shares)		862,462	0	0						0			0
Restricted Share Award Amortization	2,039	0	0	0		2,039	0	0	2,039	0	0	0	0
Share Grants to Trustees	142	1	0	0		141	0	0	142	0	0	0	0
Share Grants to Trustees (in shares)		47,500	0							0			0
Disposition of Consolidated Joint Venture	(1,391)	0	0	0		0	0	0	0	0	(1,391)	(1,391)	0
Comprehensive Income (Loss):
Other Comprehensive Loss	(51)	0	0	0		0	(51)	0	(51)	0	0	0	0
Net Loss	(55,462)	0	0	0		0	0	(49,861)	(49,861)	(5,529)	(72)	(5,601)
Net Loss, redeemable noncontrolling interest													(2,996)
Total Comprehensive Loss	(55,513)								(49,912)	(5,529)	(72)	(5,601)
Total Comprehensive Loss, redeemable noncontrolling interest													(2,996)
Balance at Dec. 31, 2009	329,590	577	0	24		487,481	(160)	(185,725)	302,197	27,126	267	27,393
Balance, redeemable noncontrolling interests at Dec. 31, 2009													14,733
Balance (in shares) at Dec. 31, 2009		57,682,917	0	2,400,000						5,637,558
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2009													3,064,252
Common Stock Issuance	420,441	1,081	0	0		419,360	0	0	420,441	0	0	0	0
Common Stock Issuance (in shares)		108,100,000	0	0						0			0
Issuance Costs	(1,293)	0	0	0		(1,293)	0	0	(1,293)	0	0	0	0
Unit Conversion	231	29	0	0		12,405	0	0	12,434	(12,203)	0	(12,203)	(230)
Unit Conversion (in shares)	2,934,511	2,934,511	0	0						(2,884,511)			(50,000)
Units Issued for Acquisitions	6,256	0	0	0		0	0	0	0	6,256	0	6,256	0
Units Issued for Acquisitions (in shares)		0	0	0						1,651,613			0
Dividends and Distributions declared:
Common Stock ($0.33, $0.20, and $0.23 per unit)	(29,277)							(29,277)	(29,277)	0	0	0
Distribution to Noncontrolling Interest in Consolidated Joint Ventures	0	0	0	0		0	0	0	0	0	0	0	0
Common Units ($0.33, $0.20, and $0.23 per unit)	(1,090)	0	0	0		0	0	0	0	(1,090)	0	(1,090)	(610)
Preferred Stock, Series A	(4,800)	0	0	0		0	0	(4,800)	(4,800)	0	0	0	0
Reallocation of Noncontrolling Interest	(6,374)	0	0	0		(6,374)	0	0	(6,374)	0	0	0	6,374
Reclassification of Noncontrolling Interests	(6,374)	0	0	0		(6,374)	0	0	(6,374)	0	0	0	6,374
Dividend Reinvestment Plan	12	0	0	0		12	0	0	12	0	0	0	0
Dividend Reinvestment Plan (in shares)		2,655	0	0						0			0
Restricted and Performance Share Award Grants	0	4	0	0		(4)	0	0	0	0	0	0	0
Restricted and Performance Share Award Grants (in shares)		437,555	0	0						0			0
Restricted Share Award Amortization	5,072	0	0	0		5,072	0	0	5,072	0	0	0	0
Share Grants to Trustees	264	1	0	0		263	0	0	264	0	0	0	0
Share Grants to Trustees (in shares)		48,000	0	0						0			0
Comprehensive Income (Loss):
Other Comprehensive Loss	(178)	0	0	0		0	(178)	0	(178)	0	0	0	0
Net Loss	(16,829)	0	0	0		0	0	(16,357)	(16,357)	(679)	207	(472)
Net Loss, redeemable noncontrolling interest													(373)
Total Comprehensive Loss	(17,007)								(16,535)	(679)	207	(472)
Total Comprehensive Loss, redeemable noncontrolling interest													(373)
Balance at Dec. 31, 2010	703,318	1,692	0	24		918,215	(338)	(236,159)	683,434	19,410	474	19,884
Balance, redeemable noncontrolling interests at Dec. 31, 2010	19,894												19,894
Balance (in shares) at Dec. 31, 2010		169,205,638	0	2,400,000					639	4,404,660
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2010													3,014,252
Common Stock Issuance	62,073	0		0			0	(39,080)	62,073	0	0	0	0
Common Stock Issuance (in shares)		0	0							0			0
Issuance Costs	(228)	0	0	0		(228)	0	0	(228)	0	0	0	0
Unit Conversion	(229)	2		0		637	0	0	639	(868)	0	(868)	(230)
Unit Conversion (in shares)	195,000	195,000	0							(245,000)			(50,000)
Units Issued for Acquisitions	204	0	46	0	0	110,931	0	0	0	204	0	204	0
Units Issued for Acquisitions (in shares)	110,977	0	4,600,000						110,977	46,404			0
Dividends and Distributions declared:
Common Stock ($0.33, $0.20, and $0.23 per unit)		0	0	0				(39,080)	(39,080)				(39,080)
Distribution to Noncontrolling Interest in Consolidated Joint Ventures			0
Common Units ($0.33, $0.20, and $0.23 per unit)	(970)	0	0	0		0	0			(970)	0	(970)	(702)
Preferred Stock, Series A	(4,800)	0	0	0		0	0	(4,800)	(4,800)	0	0	0	0
Preferred Stock, Series B	(5,699)							(5,699)	(5,699)
Reallocation of Noncontrolling Interest	3,822	0	0	0		3,835	0	0	3,835	(13)	0	(13)	(3,822)
Reclassification of Noncontrolling Interests	3,822	0	0	0		3,835	0	0	3,835	(13)	0	(13)	(3,822)
Reclassification of Noncontrolling Interests (in shares)		0	0							(3,064,252)			3,064,252
Contribution by Noncontrolling Interests in consolidated joint venture	342										342	342
Deconsolidation of consolidated joint venture	(322)										(322)	(322)
Dividend Reinvestment Plan	14	0	0	0		14	0	0	14	0	0	0	0
Dividend Reinvestment Plan (in shares)		2,933	0							0			0
Restricted and Performance Share Award Grants	1,348	5	0	0		1,343	0	0	1,348	0	0	0	0
Restricted and Performance Share Award Grants (in shares)		504,820	0							0			0
Restricted Share Award Amortization	5,765	0	0	0		5,765	0	0	5,765	0	0	0	0
Share Grants to Trustees	287			0		287	0	0	287	0	0	0	0
Share Grants to Trustees (in shares)		61,582	0							0			0
Comprehensive Income (Loss):
Other Comprehensive Loss	(813)	0	0	0		0	(813)	0	(813)	0	0	0	0
Net Loss	(26,322)	0	0	0		0	0	(25,236)	(25,236)	(899)	(187)	(1,086)
Net Loss, redeemable noncontrolling interest													(645)
Total Comprehensive Loss	(27,135)								(26,049)	(899)	(187)	(1,086)	(645)
Balance at Dec. 31, 2011	747,842	1,699		24	46	1,041,027	(1,151)	(310,974)	730,671	16,864	307	17,171
Balance, redeemable noncontrolling interests at Dec. 31, 2011	$ 14,955												$ 14,955
Balance (in shares) at Dec. 31, 2011		169,969,973		2,400,000	4,600,000					4,206,064
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2011													3,064,252