Asset Retirement Obligation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Asset Retirement Obligation [Abstract]
Asset retirement obligation, beginning balance	$ 17,031,000	$ 9,513,000
Liabilities added from acquisitions	3,634,000	80,000
Liabilities added from drilling		59,000
Sold	(58,000)
Revisions to cost estimates	(1,156,000)	6,780,000
Settlements	(186,000)	(5,000)
Accretion expense	1,099,000	604,000
Asset retirement obligation, ending balance	20,364,000	17,031,000
Legally restricted assets	$ 0	$ 0