Debt And Lines Of Credit , Narrative - Aspen Preferred OP Units and Series B-3 preferred OP units (Details) - Convertible debt - Aspen Preferred OP Units January 2024 [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Aspen Preferred OP Units [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 34.7
Conversion Price (in dollars per share)	$ 27.00	$ 68.00
Conversion of Stock, Shares Converted		0.397
Debt Instrument, Interest Rate During Period	6.50%
Series B-3 Preferred OP Units [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 11.2
Conversion Price (in dollars per share)		$ 100.00