Beneficiaries Equity of the Parent Company (Textual) (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended	14 Months Ended
	Sep. 13, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Sep. 30, 2016	Jul. 22, 2015	Nov. 05, 2013
Class of Stock [Line Items]
Dividends, Common Stock	$ 28,300,000
Preferred Stock, Dividend Rate, Percentage				6.90%		6.90%
Dividends, Preferred Stock		$ 1,725,000	$ 1,725,000	$ 5,175,000	$ 5,175,000
Shares Authorized For Equity Offering Program									16,000,000
Authorized Amount								$ 100,000,000
Number of shares available for repurchase under the preexisting share repurchase program								539,200
Repurchased and Retired, Shares				0	4,701,302		5,209,437
Share Price				$ 12.90	$ 12.92
Repurchased and Retired, Value				$ 67,300,000	$ 60,817,000
Common shares price per share		$ 0.01		$ 0.01		$ 0.01	$ 0.01
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage				6.90%
Preferred Stock, Liquidation Preference Per Share		$ 25.00		$ 25.00			$ 25.00
Dividends, Preferred Stock	$ 1,700,000
Dividend Declared [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share	$ 0.16
Redeemable Common Limited Partnership Units
Class of Stock [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share				1,479,799	1,535,102