Related-Party Transactions (Narratives) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013
WIM
Related Party Transaction [Line Items]
Term of agreement (years)	1 year
Term of renewals for agreement (years)	1 year
Prior notice to terminate agreement (days)	60 days
Monthly management fee based on gross value of assets (percent)	0.0625%
Disposition fee (percent)	0.25%
Commerce Street Building | WRES
Related Party Transaction [Line Items]
Construction management fee, tier one (percent)	4.00%
Construction management fee, threshold amount of construction costs for tier one and two	$ 500,000
Construction management fee, tier two (percent)	3.00%
Construction management fee, threshold amount of construction costs for tier two and three	1,500,000
Construction management fee, tier three (percent)	2.00%
Construction management fee related to supervision of project (percent)	1.00%
Minimum | Commerce Street Building | WRES
Related Party Transaction [Line Items]
Monthly management fee	$ 2,000
Maximum | Commerce Street Building | WRES
Related Party Transaction [Line Items]
Monthly management fee based on gross income (percent)	2.50%