Consolidated Statements Of Equity - USD ($)	Common Shares [Member] Class A Common Shares [Member]	Common Shares [Member]	Preferred Shares [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Distributions in Excess of Net Income [Member]	Total Shareholders' Equity [Member]	Noncontrolling Interests Common Units And LTIP Units [Member]	Noncontrolling Interests Shares [Member]	Noncontrolling Interests Common Units [Member]	Noncontrolling Interests Consolidated Variable Interest Entity [Member]	Total Noncontrolling Interests [Member]	Total
Balance at Dec. 31, 2013	$ 507,000		$ 76,000	$ 1,202,316,000	$ (376,000)	$ (364,568,000)	$ 837,955,000			$ 29,523,000	$ (342,000)	$ 29,181,000	$ 867,136,000
Balance (in shares) at Dec. 31, 2013		50,689,868	7,600,000						1,728,679
Unit Conversion/Redemption				(77,000)			(77,000)			(261,000)		(261,000)	$ (338,000)
Unit Conversion/Redemption (in shares)		4,725							(16,326)				4,725
Restricted Shares Forfeiture/LTIP Unit Issuance	(5,000)			5,000
Restricted Shares Forfeiture (in shares)		(487,081)											(1,948,324)
LTIP Unit Issuance (in shares)									487,081
Repurchase of Common Shares	(7,000)			(13,791,000)		(1,621,000)	(15,419,000)						$ (15,419,000)
Repurchase of Common Shares (in shares)		(656,714)
Dividends and Distributions declared:
Common Shares						(52,091,000)	(52,091,000)						(52,091,000)
Preferred Shares						(14,356,000)	(14,356,000)						(14,356,000)
Common Units										$ (1,793,000)		$ (1,793,000)	$ (1,793,000)
LTIP Units										136,000		136,000	136,000
Dividend Reinvestment Plan				50,000			50,000						$ 50,000
Dividend Reinvestment Plan (in shares)		2,162
Stock Based Compensation
Grants	2,000			647,000			649,000						649,000
Grants (in shares)		155,811
Amortization				5,397,000			5,397,000						5,397,000
Change in Fair Value of Derivative Instruments					18,000		18,000						18,000
Net Income (Loss)						67,255,000	67,255,000			$ 1,749,000	(733,000)	$ 1,016,000	68,271,000
Balance at Dec. 31, 2014	497,000		$ 76,000	1,194,547,000	(358,000)	(365,381,000)	829,381,000	$ 29,082,000		$ 29,082,000	(1,075,000)	28,007,000	$ 857,388,000
Balance (in shares) at Dec. 31, 2014		49,708,771	7,600,000					2,199,434	2,199,434
Unit Conversion/Redemption				132,000			132,000	$ (132,000)				(132,000)
Unit Conversion/Redemption (in shares)		8,965						(8,965)					8,965
Repurchase of Common Shares	(53,000)			(110,517,000)		(17,669,000)	(128,239,000)						$ (128,239,000)
Repurchase of Common Shares (in shares)		(5,310,371)
Dividends and Distributions declared:
Common Shares						(52,664,000)	(52,664,000)						(52,664,000)
Preferred Shares						(14,356,000)	(14,356,000)						(14,356,000)
Common Units								$ (1,913,000)				$ (1,913,000)	$ (1,913,000)
LTIP Units								(694,000)				(694,000)	(694,000)
Dividend Reinvestment Plan				50,000			50,000						$ 50,000
Dividend Reinvestment Plan (in shares)		2,018
Stock Based Compensation
Grants				620,000			620,000	$ 128,832					620,000
Grants (in shares)		47,985
Amortization				1,427,000			1,427,000	4,437,000				$ 4,437,000	5,864,000
Change in Fair Value of Derivative Instruments					(108,000)		(108,000)						(108,000)
Net Income (Loss)						41,796,000	41,796,000	1,096,000			(685,000)	411,000	42,207,000
Balance at Dec. 31, 2015	444,000		$ 76,000	1,086,259,000	(466,000)	(408,274,000)	678,039,000	$ 31,876,000			(1,760,000)	30,116,000	708,155,000
Balance (in shares) at Dec. 31, 2015		44,457,368	7,600,000					2,319,301
Common Units issued								$ 4,430,000				4,430,000	$ 4,430,000
Common Units issued (in shares)								225,000
Unit Conversion/Redemption (in shares)													0
LTIP Unit Issuance (in shares)													294,245
Repurchase of Common Shares	(27,000)			(52,028,000)			(52,055,000)						$ (52,055,000)
Repurchase of Common Shares (in shares)		(2,772,710)
Preferred Stock Issuance
Preferred Stock Offering, net of costs			$ 117,000	282,467,000			282,584,000						282,584,000
Preferred Stock Offering, net of costs (in shares)			11,700,000
Preferred Stock Redemption			$ (46,000)	(114,954,000)			(115,000,000)						(115,000,000)
Preferred Stock Redemption (in shares)			(4,600,000)
Dividends and Distributions declared:
Common Shares						(56,157,000)	(56,157,000)						(56,157,000)
Preferred Shares						(17,380,000)	(17,380,000)						(17,380,000)
Common Units								$ (2,356,000)				$ (2,356,000)	$ (2,356,000)
LTIP Units								(1,574,000)				(1,574,000)	(1,574,000)
Dividend Reinvestment Plan				63,000			63,000						$ 63,000
Dividend Reinvestment Plan (in shares)		3,518
Stock Based Compensation
Grants	1,000			(398,000)			(397,000)	$ 1,060,000				$ 1,060,000	663,000
Grants (in shares)		82,338						294,245
Amortization				1,417,000			1,417,000	$ 5,971,000				5,971,000	7,388,000
Change in Fair Value of Derivative Instruments					1,839,000		1,839,000						1,839,000
Exercise of Option to Acquire Noncontrolling Interest				(4,515,000)			(4,515,000)				2,197,000	2,197,000	(2,318,000)
Net Income (Loss)						116,980,000	116,980,000	4,914,000			$ (437,000)	4,477,000	121,457,000
Balance at Dec. 31, 2016	$ 418,000		$ 147,000	$ 1,198,311,000	$ 1,373,000	$ (364,831,000)	$ 835,418,000	$ 44,321,000				$ 44,321,000	$ 879,739,000
Balance (in shares) at Dec. 31, 2016		41,770,514	14,700,000					2,838,546