FAIR VALUE OF FINANCIAL ASSETS AND FINANCIAL LIABILITIES (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Total [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Total [Member]		Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Level 1 [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Level 1 [Member]		Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Level 2 [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Level 2 [Member]		Jun. 30, 2011 Fair Value, Measurements, Recurring [Member] Level 3 [Member]		Dec. 31, 2010 Fair Value, Measurements, Recurring [Member] Level 3 [Member]
Assets [Abstract]
Available-for-Sale Securities			$ 7,116,000	[1]	$ 6,720,000	[1]	$ 20,000	[1]	$ 6,720,000	[1]	$ 7,096,000	[1]	$ 0	[1]	$ 0	[1]	$ 0	[1]
Derivatives - Energy Related Assets			31,959,000	[2]	51,069,000	[2]	10,400,000	[2]	21,204,000	[2]	16,915,000	[2]	24,878,000	[2]	4,644,000	[2]	4,987,000	[2]
Total Assets			39,075,000		57,789,000		10,420,000		27,924,000		24,011,000		24,878,000		4,644,000		4,987,000
Liabilities [Abstract]
Derivatives - Energy Related Liabilities			22,833,000	[2]	50,938,000	[2]	6,962,000	[2]	19,513,000	[2]	12,989,000	[2]	23,275,000	[2]	2,882,000	[2]	8,150,000	[2]
Derivatives - Other			7,493,000	[3]	7,404,000	[3]	0	[3]	0	[3]	7,493,000	[3]	7,404,000	[3]	0	[3]	0	[3]
Total Liabilites			30,326,000		58,342,000		6,962,000		19,513,000		20,482,000		30,679,000		2,882,000		8,150,000
Changes in significant unobservable inputs [Roll forward]
Balance at beginning of period	(616,000)	(3,163,000)
Total gains and losses (realized/unrealized) included in earnings	1,565,000	(586,000)
Transfers in and/or out of Level 3, net	0	0
Settlements	813,000	5,511,000
Balance at end of period	1,762,000	1,762,000
Loss included in earnings from change in unrealized losses relating to assets and liabilities held at period end		$ 600,000

[1] Available-for-Sale Securities include securities that are traded in active markets and securities that are not traded publicly. The securities traded in active markets are valued using the quoted principal market close prices that are provided by the trustees and are categorized in Level 1 in the fair value hierarchy. The remaining securities consist of funds that are not publicly traded. These funds, which consist of stocks and bonds that are traded individually in active markets, are valued using quoted prices for similar assets and are categorized in Level 2 in the fair value hierarchy.

[2] Derivatives - Energy Related Assets and Liabilities are traded in both exchange-based and non-exchange-based markets. Exchange-based contracts are valued using unadjusted quoted market sources in active markets and are categorized in Level 1 in the fair value hierarchy. Certain non-exchange-based contracts are valued using indicative price quotations available through brokers or over-the-counter, on-line exchanges and are categorized in Level 2. These price quotations reflect the average of the bid-ask mid-point prices and are obtained from sources that management believes provide the most liquid market. For non-exchange-based derivatives that trade in less liquid markets with limited pricing information, model inputs generally would include both observable and unobservable inputs. In instances where observable data is unavailable, management considers the assumptions that market participants would use in valuing the asset or liability. This includes assumptions about market risks such as liquidity, volatility and contract duration. Such instruments are categorized in Level 3 as the model inputs generally are not observable. Management reviews and corroborates the price quotations to ensure the prices are observable which includes consideration of actual transaction volumes, market delivery points, bid-ask spreads and contract duration.

[3] Derivatives - Other are valued using quoted prices on commonly quoted intervals, which are interpolated for periods different than the quoted intervals, as inputs to a market valuation model. Market inputs can generally be verified and model selection does not involve significant management judgment.