Preferred Shares Of Beneficial Interest (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	May 08, 2015	Dec. 31, 2015
Class of Stock [Line Items]
Stock redeemed or called during period, value		$ 150,000
Series F Preferred Stock [Member]
Class of Stock [Line Items]
Stock redeemed or called during period, value	$ 150,000
Preferred stock dividends and other adjustments	$ 9,700
Preferred shares of beneficial interest, dividend percentage		6.50%
Preferred shares of beneficial interest, liquidation value per share (in dollars per share)		$ 2,500