Consolidated Statements Of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Common Shares [Member] Class A Common Shares [Member] USD ($)	Common Shares [Member]	Preferred Shares [Member] USD ($)	Additional Paid-In Capital [Member] USD ($)	Accumulated Other Comprehensive Loss [Member] USD ($)	Distributions in Excess of Net Earnings [Member] USD ($)	Total Shareholders' Equity [Member] USD ($)	Noncontrolling Interests Shares [Member]	Noncontrolling Interests Common Units [Member] USD ($)	Noncontrolling Interests Consolidated Joint Ventures [Member] USD ($)	Noncontrolling Interests Consolidated Variable Interest Entity [Member] USD ($)	Noncontrolling Interests [Member] USD ($)	Redeemable Noncontrolling Interests Shares [Member]	Redeemable Noncontrolling Interests Common Units [Member] USD ($)	Total USD ($)
Balance, redeemable noncontrolling interests at Dec. 31, 2010														$ 19,894
Balance at Dec. 31, 2010	1,692		24	918,215	(338)	(236,159)	683,434		19,410	474		19,884			703,318
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2010													3,014,252
Balance (in shares) at Dec. 31, 2010		169,205,638	2,400,000					4,404,660
Unit Conversion	2			637			639		(868)			(868)		230	(229)
Unit Conversion (in shares)		195,000						(245,000)					50,000		195,000
Reclassification / Reallocation of Noncontrolling Interest				3,835			3,835		(13)			(13)		(3,822)	3,822
Preferred Stock Issuance
Preferred Stock Offering, net of costs			46	110,931			110,977								110,977
Preferred Stock Offering, net of costs (in shares)			4,600,000
Common Stock Issuance
Common Units Issued for Acquisitions									204			204			204
Common Units Issued for Acquisitions (in shares)								46,404
Dividends and Distributions declared:
Common Stock ($0.23 and $0.24 per share)						(39,080)	(39,080)								(39,080)
Preferred Stock						(10,499)	(10,499)								(10,499)
Common Units ($0.23 and $0.24 per share)									(969)			(969)		(702)	(969)
Dividend Reinvestment Plan				14			14								14
Dividend Reinvestment Plan (in shares)		2,933
Stock Based Compensation
Grants	5			1,630			1,635								1,635
Grants (in shares)		566,402
Amortization				5,765			5,765								5,765
Contribution by Noncontrolling Interests in Consolidated Joint Ventures										342		342			342
Deconsolidation of Consolidated Joint Ventures										(322)		(322)			(322)
Change in Fair Value of Derivative Instruments					(813)		(813)								(813)
Net Income (Loss)						(25,234)	(25,234)		(902)	(187)		(1,089)		(645)	(26,323)
Balance, redeemable noncontrolling interests at Dec. 31, 2011														14,955
Balance at Dec. 31, 2011	1,699		70	1,041,027	(1,151)	(310,972)	730,673		16,862	307		17,169		14,955	747,842
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2011													3,064,252
Balance (in shares) at Dec. 31, 2011		169,969,973	7,000,000					4,206,064
Unit Conversion	1			571			572		(572)			(572)
Unit Conversion (in shares)		157,810						(157,810)							157,810
Reclassification / Reallocation of Noncontrolling Interest				(966)			(966)							966	(966)
Common Stock Issuance
Common Stock Offering, net of costs	240			128,318			128,558								128,558
Common Stock Offering, net of costs (in shares)		24,000,000
Common Stock Option Cancellation	25			(25)
Common Stock Option Cancellation (in shares)		2,521,561
Dividends and Distributions declared:
Common Stock ($0.23 and $0.24 per share)						(46,138)	(46,138)								(46,138)
Preferred Stock						(14,000)	(14,000)								(14,000)
Common Units ($0.23 and $0.24 per share)									(991)			(991)		(736)	(991)
Dividend Reinvestment Plan				24			24								24
Dividend Reinvestment Plan (in shares)		5,117
Stock Based Compensation
Grants	21			2,616			2,637								2,637
Grants (in shares)		2,017,895
Amortization				6,727			6,727								6,727
Consolidation of Variable Interest Entity											956	956			956
Deconsolidation of Consolidated Joint Ventures										(307)		(307)			(307)
Change in Fair Value of Derivative Instruments					(635)		(635)								(635)
Net Income (Loss)						22,376	22,376		185		(480)	(295)		136	22,081
Balance, redeemable noncontrolling interests at Dec. 31, 2012															15,321
Balance at Dec. 31, 2012	1,986		70	1,178,292	(1,786)	(348,734)	829,828		15,484		476	15,960		15,321	845,788
Balance (in shares) at Dec. 31, 2012		198,672,356	7,000,000					4,048,254
Balance, redeemable noncontrolling interests (in shares) at Dec. 31, 2012													3,064,252
Unit Conversion	1			(234)			(233)		(766)			(766)			(999)
Unit Conversion (in shares)		27,790						(197,790)							27,790
Reclassification / Reallocation of Noncontrolling Interest									15,365			15,365		(15,365)	15,365
Reclassification / Reallocation of Noncontrolling Interest (in shares)								3,064,252					(3,064,252)
Preferred Stock Issuance
Preferred Stock Offering, net of costs			30	72,340			72,370								72,370
Preferred Stock Offering, net of costs (in shares)			3,000,000
Preferred Stock Redemption			(24)	(59,976)			(60,000)								(60,000)
Preferred Stock Redemption (in shares)			(2,400,000)
Dividends and Distributions declared:
Common Stock ($0.23 and $0.24 per share)						(50,836)	(50,836)								(50,836)
Preferred Stock						(14,611)	(14,611)								(14,611)
Common Units ($0.23 and $0.24 per share)									(1,669)			(1,669)			(1,669)
Dividend Reinvestment Plan				38			38								38
Dividend Reinvestment Plan (in shares)		7,206
Stock Based Compensation
Grants	41			467			508								508
Grants (in shares)		4,052,067
Amortization				9,871			9,871								9,871
Change in Fair Value of Derivative Instruments					1,410		1,410								1,410
Net Income (Loss)						49,613	49,613		1,109		(818)	291		44	49,904
Balance at Dec. 31, 2013	$ 2,028		$ 76	$ 1,200,798	$ (376)	$ (364,568)	$ 837,958		$ 29,523		$ (342)	$ 29,181			$ 867,139
Balance (in shares) at Dec. 31, 2013		202,759,419	7,600,000					6,914,716