Fair Value Measurements (Recurring Fair Value Measures Of Assets And Liabilities) (Details) (USD $)	Dec. 31, 2012		Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents - Money Market Mutual Funds	$ 33,215,000		$ 46,113,000
Hedging Collateral Deposits	0		364,000
Total Assets	104,580,000		103,890,000
Total Liabilities	13,816,000		24,527,000
Total Net Assets/(Liabilities)	90,764,000		79,363,000
Commodity Futures Contracts - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	630,000		1,588,000
Derivative Financial Instruments	0		0
Over The Counter Swaps - Oil [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	(427,000)		0
Derivative Financial Instruments	14,609,000		20,318,000
Over The Counter Swaps - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	36,932,000		26,028,000
Derivative Financial Instruments	(793,000)		4,209,000
Balanced Equity Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	28,586,000		24,767,000
Common Stock - Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	5,371,000		4,758,000
Other Common Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	273,000		272,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents - Money Market Mutual Funds	33,215,000		46,113,000
Hedging Collateral Deposits			364,000
Total Assets	70,286,000		80,622,000
Total Liabilities	2,211,000		2,760,000
Total Net Assets/(Liabilities)	68,075,000		77,862,000
Fair Value, Inputs, Level 1 [Member] | Commodity Futures Contracts - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	2,841,000		4,348,000
Derivative Financial Instruments	2,211,000		2,760,000
Fair Value, Inputs, Level 1 [Member] | Over The Counter Swaps - Oil [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	0		0
Derivative Financial Instruments	0		0
Fair Value, Inputs, Level 1 [Member] | Over The Counter Swaps - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	0		0
Derivative Financial Instruments	0		0
Fair Value, Inputs, Level 1 [Member] | Balanced Equity Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	28,586,000		24,767,000
Fair Value, Inputs, Level 1 [Member] | Common Stock - Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	5,371,000		4,758,000
Fair Value, Inputs, Level 1 [Member] | Other Common Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	273,000		272,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents - Money Market Mutual Funds	0		0
Hedging Collateral Deposits			0
Total Assets	59,169,000		41,751,000
Total Liabilities	22,391,000		20,586,000
Total Net Assets/(Liabilities)	36,778,000		21,165,000
Fair Value, Inputs, Level 2 [Member] | Commodity Futures Contracts - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	0		0
Derivative Financial Instruments	0		0
Fair Value, Inputs, Level 2 [Member] | Over The Counter Swaps - Oil [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	186,000		0
Derivative Financial Instruments	1,133,000		654,000
Fair Value, Inputs, Level 2 [Member] | Over The Counter Swaps - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	58,983,000		41,751,000
Derivative Financial Instruments	21,258,000		19,932,000
Fair Value, Inputs, Level 2 [Member] | Balanced Equity Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0		0
Fair Value, Inputs, Level 2 [Member] | Common Stock - Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0		0
Fair Value, Inputs, Level 2 [Member] | Other Common Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0		0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents - Money Market Mutual Funds	0		0
Hedging Collateral Deposits			0
Total Assets	719,000		559,000
Total Liabilities	14,808,000		20,223,000
Total Net Assets/(Liabilities)	(14,089,000)		(19,664,000)
Fair Value, Inputs, Level 3 [Member] | Commodity Futures Contracts - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	0		0
Derivative Financial Instruments	0		0
Fair Value, Inputs, Level 3 [Member] | Over The Counter Swaps - Oil [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	719,000		559,000
Derivative Financial Instruments	14,808,000		20,223,000
Fair Value, Inputs, Level 3 [Member] | Over The Counter Swaps - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	0		0
Derivative Financial Instruments	0		0
Fair Value, Inputs, Level 3 [Member] | Balanced Equity Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0		0
Fair Value, Inputs, Level 3 [Member] | Common Stock - Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0		0
Fair Value, Inputs, Level 3 [Member] | Other Common Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0		0
Netting Adjustments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents - Money Market Mutual Funds	0	[1]	0	[1]
Hedging Collateral Deposits			0	[1]
Total Assets	(25,594,000)	[1]	(19,042,000)	[1]
Total Liabilities	(25,594,000)	[1]	(19,042,000)	[1]
Total Net Assets/(Liabilities)	0	[1]	0	[1]
Netting Adjustments [Member] | Commodity Futures Contracts - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	(2,211,000)	[1]	(2,760,000)	[1]
Derivative Financial Instruments	(2,211,000)	[1]	(2,760,000)	[1]
Netting Adjustments [Member] | Over The Counter Swaps - Oil [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	(1,332,000)	[1]	(559,000)	[1]
Derivative Financial Instruments	(1,332,000)	[1]	(559,000)	[1]
Netting Adjustments [Member] | Over The Counter Swaps - Gas [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Financial Instruments	(22,051,000)	[1]	(15,723,000)	[1]
Derivative Financial Instruments	(22,051,000)	[1]	(15,723,000)	[1]
Netting Adjustments [Member] | Balanced Equity Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0	[1]	0	[1]
Netting Adjustments [Member] | Common Stock - Financial Services Industry [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	0	[1]	0	[1]
Netting Adjustments [Member] | Other Common Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Investments	$ 0	[1]	$ 0	[1]

[1] Amounts represent the impact of legally-enforceable master netting arrangements that allow the Company to net gain and loss positions held with the same counterparties.