Investment in Unconsolidated Entities (Details Textual) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Class B Interest Held	$ 16.5		$ 11.8
Percentage of interest in joint venture	9.00%
HSRE and DCV Holdings [Member]
Percentage of interest in joint venture	5.22%
Class A Interest Held	33.0
Cb Portfolio [Member]
Equity method investment, ownership percentage	47.20%	[1]
Hsre Campus Crest Llc [Member]
Cost of investment	$ 65.6
Equity method investment, ownership percentage	30.00%

[1] At September 30, 2013, our effective interest in the CB Portfolio was 47.2%. As of October 1, 2013, our interest in the Copper Beech portfolio was amended as noted below in the Amendment to Copper Beech Purchase Agreement.