Comprehensive (Loss) Income (Details) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Comprehensive (loss) income
Net income (loss)	$ 8,637	$ (22,720)	$ 6,680	$ (24,570)
Unrealized gain on cash flow hedge, net of deferred taxes			6,884
Other	0	(32)	38	(44)
Comprehensive (loss) income	12,150	(19,832)	13,602	(21,048)
Interest rate swaps [Member]
Comprehensive (loss) income
Unrealized gain on cash flow hedge, net of deferred taxes	3,549	2,758	6,880	3,570
Comprehensive (Loss) Income (Textuals) [Abstract]
Unrealized gain on cash flow hedge, deferred tax	1,982	1,577	3,818	2,029
Natural Gas Swaps [Member]
Comprehensive (loss) income
Unrealized gain on cash flow hedge, net of deferred taxes	(36)	162	4	(4)
Comprehensive (Loss) Income (Textuals) [Abstract]
Unrealized gain on cash flow hedge, deferred tax	$ (20)	$ 105	$ 2	$ 0

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The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

+ References

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-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
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The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 19
-Article 5

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-Name Emerging Issues Task Force (EITF)
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-Name Statement of Financial Accounting Standard (FAS)
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This element represents Other Comprehensive Income (Loss), Net of Tax, for the period. Includes deferred gains (losses) on qualifying hedges, unrealized holding gains (losses) on available-for-sale securities, minimum pension liability, and cumulative translation adjustment.

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-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
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-Paragraph 38
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-Name Regulation S-X (SX)
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Change in accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges, net of tax effect. The after tax effect change includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.

+ References

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Tax effect on the change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's increase (decrease) in deferred hedging gains or losses.

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