Derivative Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2012

Derivative Financial Instruments [Abstract]

Effect of derivative instruments on the statement of operations

	Amount of Loss Recognized in OCI on Derivative (Effective Portion)						Amount Reclassified from Accumulated OCI into Income
Derivatives in Cash Flow Hedging Relationships	Three Months Ended June 30, 2012		Three Months Ended June 30, 2011			Location of Amount Reclassified from Accumulated OCI into Income	Three Months Ended June 30, 2012		Three Months Ended June 30, 2011
Interest rate swaps	$	—	$	(141	)	Interest expense, net of amounts capitalized	$	—	$	5,672
Natural gas swaps		—		(115	)	Operating Costs		—		58
Total	$	—	$	(256	)	Total	$	—	$	5,730

	Amount of Loss Recognized in OCI on Derivative (Effective Portion)						Amount Reclassified from Accumulated OCI into Income
Derivatives in Cash Flow Hedging Relationships	Six Months Ended June 30, 2012		Six Months Ended June 30, 2011			Location of Amount Reclassified from Accumulated OCI into Income	Six Months Ended June 30, 2012		Six Months Ended June 30, 2011
Interest rate swaps	$	—	$	(427	)	Interest expense, net of amounts capitalized	$	—	$	11,125
Natural gas swaps		—		(209	)	Operating Costs		—		215
Total	$	—	$	(636	)	Total	$	—	$	11,340