Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2013

Fair Value Measurements

Derivative instrument assets and liabilities measured at fair value on a recurring basis

			Fair value measurements at reporting date using
Description	September 30, 2013		Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
	(Thousands)
Assets
Derivative instruments, at fair value	$	203,002	$	453	$	133,413	$	69,136
Liabilities
Derivative instruments, at fair value	$	18,353	$	647	$	16,891	$	815

			Fair value measurements at reporting date using
Description	December 31, 2012		Quoted prices in active markets for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
	(Thousands)
Assets
Derivative instruments, at fair value	$	304,237	$	1,228	$	204,592	$	98,417
Liabilities
Derivative instruments, at fair value	$	75,562	$	1,609	$	66,250	$	7,703

Fair value measurements using significant unobservable inputs (Level 3)

	Fair value measurements using significant unobservable inputs (Level 3)
	Derivative instruments, at fair value, net Three Months Ended September 30,					Derivative instruments, at fair value, net Nine Months Ended September 30,
	2013			2012		2013		2012
	(Thousands)
Beginning of period	$	74,688		$	129,436	$	90,714	$	143,260
Total gains or losses:
Included in earnings	414			(90)		(341)		(90		)
Included in OCI	2,067			(13,839)		3,459		13,554
Purchases	(79		)	22		(7)		(994		)
Settlements	(8,769		)	(18,558)		(25,504)		(58,759		)
Transfers in and/or out of Level 3	–			–		–		–
End of period	$	68,321		$	96,971	$	68,321	$	96,971