Derivatives (Summary Of Derivative Instruments Contracts) (Details)	Mar. 31, 2016 MMBTU $ / MMBTU bbl	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	100,000
Natural Gas Costless Collars [Member] | Fixed Price Two [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000	70,000
Natural Gas Costless Collars [Member] | Fixed Price Three [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	200,000	50,000
Natural Gas Costless Collars [Member] | Fixed Price Four [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000	70,000
Natural Gas Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	50,000
Natural Gas Fixed Price Swaps [Member] | Fixed Price Six [Member]
Derivative [Line Items]
Production volume covered per month - Natural Gas | MMBTU	80,000
Contract price	2.43
Oil Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl		10,000
Oil Costless Collars [Member] | Fixed Price Seven [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl	10,000
Oil Costless Collars [Member] | Fixed Price Eight [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl	5,000
Oil Costless Collars [Member] | Fixed Price Nine [Member]
Derivative [Line Items]
Production volume covered per month - Oil | bbl	3,000
Oil Fixed Price Swaps [Member] | Fixed Price Six [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 Seven [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	3.50
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Two [Member]
Derivative [Line Items]
Contract price	2.15	3.25
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Three [Member]
Derivative [Line Items]
Contract price	1.95	3.50
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Four [Member]
Derivative [Line Items]
Contract price	2.15	3.50
Minimum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Contract price	2.25
Minimum [Member] | Oil Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Contract price | $ / bbl		80.00
Minimum [Member] | Oil Costless Collars [Member] | Fixed Price Seven [Member]
Derivative [Line Items]
Contract price	37.50
Minimum [Member] | Oil Costless Collars [Member] | Fixed Price Eight [Member]
Derivative [Line Items]
Contract price	37.50
Minimum [Member] | Oil Costless Collars [Member] | Fixed Price Nine [Member]
Derivative [Line Items]
Contract price	35.00
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price One [Member]
Derivative [Line Items]
Contract price	3.10	4.10
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Two [Member]
Derivative [Line Items]
Contract price	2.50	4.00
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Three [Member]
Derivative [Line Items]
Contract price	2.40	4.00
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Four [Member]
Derivative [Line Items]
Contract price	2.90	3.95
Maximum [Member] | Natural Gas Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Contract price	3.65
Maximum [Member] | Oil Costless Collars [Member] | Fixed Price Five [Member]
Derivative [Line Items]
Contract price | $ / bbl		86.50
Maximum [Member] | Oil Costless Collars [Member] | Fixed Price Seven [Member]
Derivative [Line Items]
Contract price	44.00
Maximum [Member] | Oil Costless Collars [Member] | Fixed Price Eight [Member]
Derivative [Line Items]
Contract price	46.50
Maximum [Member] | Oil Costless Collars [Member] | Fixed Price Nine [Member]
Derivative [Line Items]
Contract price	49.00