Organization and Summary of Significant Accounting Policies (Schedule of Changes in Asset Retirement Obligations) (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Organization and Summary of Significant Accounting Policies [Abstract]
Balance, beginning of period	$ 1,571	$ 1,513	$ 1,513
Liabilities incurred	36		19
Accretion expense	140		$ 39
Revisions in estimated cash flows	778
Balance, end of period	$ 2,525		$ 1,571