Derivatives (Summary Of Derivative Instruments Contracts) (Details)	Dec. 31, 2015 MMBTU $ / MMBTU	Sep. 30, 2015 MMBTU $ / MMBTU $ / bbl bbl
Natural Gas Costless Collars [Member] | Fixed Price One [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000
Natural Gas Costless Collars [Member] | Fixed Price Two [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000
Natural Gas Costless Collars [Member] | Fixed Price Three [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	200,000
Natural Gas Costless Collars [Member] | Fixed Price Four [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	100,000
Natural Gas Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	100,000
Natural Gas Costless Collars [Member] | Fixed Price Six [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000
Natural Gas Costless Collars [Member] | Fixed Price Eight [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU		100,000
Natural Gas Costless Collars [Member] | Fixed Price Nine [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU		70,000
Natural Gas Costless Collars [Member] | Fixed Price Ten [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU		50,000
Natural Gas Costless Collars [Member] | Fixed Price Eleven [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU		70,000
Natural Gas Fixed Price Swaps [Member] | Fixed Price Seven [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000
Contract price	2.43
Oil Costless Collars [Member] | Fixed Price Twelve [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl		10,000
Oil Fixed Price Swaps [Member] | Fixed Price Thirteen [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl		5,000
Contract price | $ / bbl		94.56
Oil Fixed Price Swaps [Member] | Fixed Price Fourteen [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl		7,000
Contract price | $ / bbl		93.91
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price One [Member]
Derivative [Line Items]
Contract price	2.50
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Two [Member]
Derivative [Line Items]
Contract price	2.15
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Three [Member]
Derivative [Line Items]
Contract price	1.95
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Four [Member]
Derivative [Line Items]
Contract price	1.75
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Contract price	2.00
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Six [Member]
Derivative [Line Items]
Contract price	2.15
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Eight [Member]
Derivative [Line Items]
Contract price		3.50
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Nine [Member]
Derivative [Line Items]
Contract price		3.25
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Ten [Member]
Derivative [Line Items]
Contract price		3.50
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Eleven [Member]
Derivative [Line Items]
Contract price		3.50
Minimum [Member] | Oil Costless Collars [Member] | Fixed Price Twelve [Member]
Derivative [Line Items]
Contract price | $ / bbl		80.00
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price One [Member]
Derivative [Line Items]
Contract price	3.10
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Two [Member]
Derivative [Line Items]
Contract price	2.50
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Three [Member]
Derivative [Line Items]
Contract price	2.40
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Four [Member]
Derivative [Line Items]
Contract price	1.90
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Contract price	2.60
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Six [Member]
Derivative [Line Items]
Contract price	2.90
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Eight [Member]
Derivative [Line Items]
Contract price		4.10
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Nine [Member]
Derivative [Line Items]
Contract price		4.00
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Ten [Member]
Derivative [Line Items]
Contract price		4.00
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Eleven [Member]
Derivative [Line Items]
Contract price		3.95
Maximum [Member] | Oil Costless Collars [Member] | Fixed Price Twelve [Member]
Derivative [Line Items]
Contract price | $ / bbl		86.50