Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Summary of reconciliation of the ARO
Balance at beginning of period	$ 3,095	$ 2,968
Accretion expense	70	63
Additions during period	5
Balance at end of period	$ 3,170	$ 3,031