Summary Of Significant Accounting Policies (Schedule of Differences Between Book Value and Tax Basis of Net Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary Of Significant Accounting Policies [Abstract]
Financial statement basis of net assets	$ 7,292	$ 8,850	$ 10,665
Tax basis of net assets (unaudited)	7,751	8,626
Difference	$ (459)	$ 224