Related Party Transactions (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) fiscal_quarter	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Asset management fees	$ 2,109,000	$ 2,312,000	$ 2,263,000
Number of fiscal quarters immediately preceding the date reimbursement is sought | fiscal_quarter	4
Administrative services cost incurred	$ 5,553,000	4,842,000	5,964,000
Property management fees	1,614,000	1,924,000	1,842,000
Payables to related parties	529,000	747,000
Behringer Harvard Opportunity Advisors I
Related Party Transaction [Line Items]
Asset management fees	$ 2,000,000	2,300,000	2,300,000
Acquisition and advisory fees as a percentage of contract purchase price	2.50%
Acquisition and advisory fees as a percentage of funds advanced in respect of loan investment	2.50%
Acquisition and advisory fees	$ 100,000	300,000	200,000
Debt financing fees	$ 0	0	600,000
Advisor's operating expenses as a percentage of average invested assets	2.00%
Advisor's operating expenses as percentage of net income other than any additions to non cash reserves and any gain from sale of assets	25.00%
Obligation to reimburse advisor	$ 1,660,000
Administrative services cost incurred	$ 1,200,000	1,400,000	1,700,000
Behringer Harvard Opportunity Advisors I | Advisory Agreement
Related Party Transaction [Line Items]
Basis points due to advisor for revised loan, year one	40.00%
Basis points due to advisor for revised loan, year two	30.00%
Basis points due to advisor for revised loan, year three	30.00%
Behringer Harvard Opportunity Advisors I | Maximum
Related Party Transaction [Line Items]
Administrative services cost incurred		1,700,000
Behringer Harvard Opportunity Advisors I | First Year of Any Extension | Minimum | Advisory Agreement
Related Party Transaction [Line Items]
Extension term	120 days
Behringer Harvard Opportunity Advisors I | Extension of Three or More Years | Maximum | Advisory Agreement
Related Party Transaction [Line Items]
Advisor's debt financing fee as a percentage of loan commitment amount	1.00%
Maximum debt financing fee for an extension of three or more years	1.00%
Behringer Harvard Opportunity Advisors I | Scenario, Forecast
Related Party Transaction [Line Items]
Obligation to reimburse advisor				$ 1,660,000
The Ablon at Frisco Square
Related Party Transaction [Line Items]
Acquisition and advisory fees		200,000
BH Property Management
Related Party Transaction [Line Items]
Advisor's and property management fee as a percentage of gross revenue	4.50%
Oversight fee as a percentage of gross revenues of the property managed	0.50%
Property management fees	$ 200,000	700,000	$ 900,000
Advisor and Affiliates
Related Party Transaction [Line Items]
Payables to related parties	$ 500,000	$ 800,000
After Amendment
Related Party Transaction [Line Items]
Asset management fee as a percentage of aggregate asset value of acquired real estate and real estate related assets	0.575%