Derivative Instruments (Gross Fair Values of Receivable and Payable Affiliate Balances) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	$ 1,497,800	$ 2,582,700
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(298,700)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	1,199,100	2,582,700
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Of Recognized Liabilities	(344,200)
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Offset In The Balance Sheets	298,700
Affiliate Balances, Offsetting Derivative Liabilities, Net Amount Of Liabilities Presented In The Balance Sheets	(45,500)
Accounts receivable monetized gains-affiliate [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	851,800	1,562,200
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(71,000)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	780,800	1,562,200
Long-term accounts receivable monetized gains-affiliate [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	170,300	1,020,500
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(170,300)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets		1,020,500
Short-term swaps [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	196,600
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(16,700)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	179,900
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Of Recognized Liabilities	(16,700)
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Offset In The Balance Sheets	16,700
Affiliate Balances, Offsetting Derivative Liabilities, Net Amount Of Liabilities Presented In The Balance Sheets
Short-Term Puts [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	37,800
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	37,800
Total Short-Term Derivatives [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	234,400
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(16,700)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	217,700
Long-term swaps [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	87,000
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(40,700)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	46,300
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Of Recognized Liabilities	(40,700)
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Offset In The Balance Sheets	40,700
Affiliate Balances, Offsetting Derivative Liabilities, Net Amount Of Liabilities Presented In The Balance Sheets
Total Commodity Swap [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Of Recognized Liabilities	(57,400)
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Offset In The Balance Sheets	57,400
Affiliate Balances, Offsetting Derivative Liabilities, Net Amount Of Liabilities Presented In The Balance Sheets
Long-Term Puts [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	154,300
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	154,300
Total Long-Term Derivatives [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Of Recognized Assets	241,300
Affiliate Balances, Offsetting Derivative Assets, Gross Amounts Offset In The Balance Sheets	(40,700)
Affiliate Balances, Offsetting Derivative Assets, Net Amount Of Assets Presented In The Balance Sheets	200,600
Put premiums payable-affiliate [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Of Recognized Liabilities	(71,000)
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Offset In The Balance Sheets	71,000
Affiliate Balances, Offsetting Derivative Liabilities, Net Amount Of Liabilities Presented In The Balance Sheets
Long-Term Put Premiums Payable-Affiliate [Member]
Derivative [Line Items]
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Of Recognized Liabilities	(215,800)
Affiliate Balances, Offsetting Derivative Liabilities, Gross Amounts Offset In The Balance Sheets	170,300
Affiliate Balances, Offsetting Derivative Liabilities, Net Amount Of Liabilities Presented In The Balance Sheets	$ (45,500)