Investment in Joint Venture (Details Textual) (USD $)	Jun. 30, 2012 properties	Dec. 31, 2011	Jun. 30, 2012 Manhattan Collection Joint Venture [Member] properties	Jul. 29, 2011 Manhattan Collection Joint Venture [Member] properties
Investment in Joint Venture (Textual) [Abstract]
Equity interest issued in a joint venture			49.00%	49.00%
Number of properties owned	21		6	6
Total assets of joint venture			$ 538,700,000
Amount existing first mortgage and mezzanine debt			566,900,000
Preferred capital	$ 90,000	$ 90,000	$ 76,600,000