Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Measurements [Abstract]

Schedule Of Fair Value Of Financial Assets And Liabilities By Level

As of December 31, 2012		Total		Level 1		Level 2		Level 3
Assets from commodity derivative instruments	$	122,143	$	-	$	122,143	$	-
	$	122,143	$	-	$	122,143	$	-
Liabilities from commodity derivative instruments	$	13,484	$	-	$	13,484	$	-
Liabilities from interest rate derivative instruments		12,236		-		12,236		-
	$	25,720	$	-	$	25,720	$	-
As of December 31, 2011	Total		Level 1		Level 2			Level 3
Assets from commodity derivative instruments	$	105,477	$	-	$	105,477	$	-
Assets from interest rate derivative instruments		20		-		20		-
	$	105,497	$	-	$	105,497	$	-
Liabilities from commodity derivative instruments	$	10,085	$	-	$	10,085	$	-
Liabilities from interest rate derivative instruments		23,973		-		23,973		-
	$	34,058	$	-	$	34,058	$	-