Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	$ 54,000	$ 27,365,000
Liabilities [Abstract]
NYMEX Fixed Price Derivative contracts	9,012,000	0
Derivative Assets (Liabilities) - net [Roll Forward]
Unobservable inputs at December 31, 2015	5,634
Changes in market value	(2,385)
Settlements during the period	(3,483)
Unobservable inputs at December 31, 2016	(234)
Recurring Basis [Member]
Assets [Abstract]
Total Assets	54,000	27,365,000
Liabilities [Abstract]
Total Liabilities	9,012,000	0
Recurring Basis [Member] | Fixed Price Derivative Contracts [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	35,000	21,731,000
Liabilities [Abstract]
NYMEX Fixed Price Derivative contracts	8,759,000	0
Recurring Basis [Member] | Collars [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	19,000
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets [Abstract]
Total Assets	0	0
Liabilities [Abstract]
Total Liabilities	0	0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Price Derivative Contracts [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	0	0
Liabilities [Abstract]
NYMEX Fixed Price Derivative contracts	0	0
Recurring Basis [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Collars [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	0
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets [Abstract]
Total Assets	35,000	21,731,000
Liabilities [Abstract]
Total Liabilities	8,759,000	0
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fixed Price Derivative Contracts [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	35,000	21,731,000
Liabilities [Abstract]
NYMEX Fixed Price Derivative contracts	8,759,000	0
Recurring Basis [Member] | Significant Other Observable Inputs (Level 2) [Member] | Collars [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	0
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets [Abstract]
Total Assets	19,000	5,634,000
Liabilities [Abstract]
Total Liabilities	253,000	0
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fixed Price Derivative Contracts [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	0	0
Liabilities [Abstract]
NYMEX Fixed Price Derivative contracts	0	$ 0
Recurring Basis [Member] | Significant Unobservable Inputs (Level 3) [Member] | Collars [Member]
Assets [Abstract]
NYMEX Fixed Price Derivative contracts	$ 19,000