Investment in Unconsolidated Entities (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2013
Schedule of Equity Method Investments [Line Items]
Number of Properties, In Operations		18
Net Total Investment		$ 93,783	$ 259,740
Amount Outstanding		$ 511,725
Debt, Weighted Average Interest Rate		4.12%
Cb Portfolio [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		48.00%		19.00%
Year Founded		2013
Number of Properties, In Operations		7
Net Total Investment		$ 50,674
Amount Outstanding	[1]	$ 195,791
Debt, Weighted Average Interest Rate	[2]	5.41%
Debt, Maturity Start Date		Oct. 01, 2015
Debt, Maturity End Date		Oct. 01, 2020
HSRE Campus Crest I LLC [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		63.90%
Year Founded		2009
Number of Properties, In Operations		1
Net Total Investment		$ 3,719
Amount Outstanding	[1]	$ 11,166
Debt, Weighted Average Interest Rate	[3]	2.68%
Maturity Date	[4]	May 09, 2015
HSRE Campus Crest V LLC [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		10.00%
Year Founded		2011
Number of Properties, In Operations		2
Net Total Investment		$ 0
Amount Outstanding	[1]	$ 36,289
Debt, Weighted Average Interest Rate	[3]	2.88%
Debt, Maturity Start Date	[4]	May 05, 2015
Debt, Maturity End Date	[4]	Jul. 20, 2015
HSRE Campus Crest VI LLC [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		20.00%
Year Founded		2012
Number of Properties, In Operations		3
Net Total Investment		$ 6,645
Amount Outstanding	[1]	$ 53,706
Debt, Weighted Average Interest Rate	[3]	2.49%
Debt, Maturity Start Date	[4]	May 08, 2015
Debt, Maturity End Date	[4]	Dec. 19, 2015
HSRE Campus Crest IX LLC [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		30.00%
Year Founded		2013
Number of Properties, In Operations		1
Net Total Investment		$ 19,394
Amount Outstanding	[1]	$ 90,081
Debt, Weighted Average Interest Rate	[3]	2.38%
Maturity Date		Jul. 25, 2016
HSRE Campus Crest X LLC [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		30.00%
Year Founded		2013
Number of Properties, In Operations		2
Net Total Investment		$ 7,836
Amount Outstanding	[1]	$ 42,579
Debt, Weighted Average Interest Rate	[3]	2.36%
Debt, Maturity Start Date		Sep. 06, 2016
Debt, Maturity End Date		Sep. 30, 2018
CSH Montreal LP [Member]
Schedule of Equity Method Investments [Line Items]
Our Ownership		47.00%	47.00%
Year Founded		2013
Number of Properties, In Operations		2
Net Total Investment		$ 5,515
Amount Outstanding	[1]	$ 82,113
Debt, Weighted Average Interest Rate	[3]	5.69%
Maturity Date		Jan. 13, 2016

[1] The amount outstanding for debt represents 100% of the debt outstanding at each of the respective joint ventures in which the Company has varying ownership percentages. See Note 17 for a discussion of amounts of the outstanding debt in which the Company guarantees on behalf of certain of these joint ventures.

[2] Comprised of fixed rate debt.

[3] Variable interest rates.

[4] Certain loans which matured in May 2015 and are scheduled to mature during July 2015 are in the process of being refinanced as of the date of this filing.