Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Measurements [Abstract]

Carrying Amount and Estimated Fair Values of Financial Instruments

	June 30,				December 31,
	2013				2012
	Carrying		Fair		Carrying		Fair
	Amount		Value		Amount		Value
	(in thousands)
Cash and cash equivalents	$	25,685	$	25,685	$	53,583	$	53,583
Restricted cash	$	–	$	–	$	8,542	$	8,542
Unsecured revolving credit facility	$	230,000	$	230,000	$	–	$	–
Senior notes	$	1,668,934	$	1,791,429	$	1,669,473	$	1,917,005
Derivative instruments	$	264,201	$	264,201	$	287,878	$	287,878

Summary Assets and Liabilities Measured at Fair Value on Recurring Basis

	June 30, 2013
	Fair Value Measurements Using:
	Quoted Prices		Significant
	in Active		Other		Significant
	Markets		Observable Inputs		Unobservable Inputs		Assets (Liabilities)
	(Level 1)		(Level 2)		(Level 3)		at Fair Value
Derivative assets	$	–	$	295,761	$	10,967	$	306,728
Derivative liabilities		–		(3,602)		(38,925)		(42,527)
Total	$	–	$	292,159	$	(27,958)	$	264,201
	December 31, 2012
	Fair Value Measurements Using:
	Quoted Prices		Significant
	in Active		Other		Significant
	Markets		Observable Inputs		Unobservable Inputs		Assets (Liabilities)
	(Level 1)		(Level 2)		(Level 3)		at Fair Value
Derivative assets	$	–	$	287,993	$	4,151	$	292,144
Derivative liabilities		–		–		(4,266)		(4,266)
Total	$	–	$	287,993	$	(115)	$	287,878

Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3), Reconciliation

	For the three months ended				For the six months ended
	June 30,				June 30,
	2013		2012		2013		2012
	(in thousands)
Balance at beginning of period	$	(60,147)	$	184,543	$	(115)	$	182,119
Total gains or losses (realized/unrealized):
Included in earnings		32,277		65,274		(26,748)		123,736
Included in other comprehensive income		–		(77,731)		–		(77,441)
Purchases, issuances, and settlements:
Purchases		–		–		–		–
Issuances		–		–		–		–
Settlements		(88)		(65,864)		(1,095)		(122,192)
Transfers into/out of Level 3		–		–		–		–
Balance at end of period	$	(27,958)	$	106,222	$	(27,958)	$	106,222
Change in unrealized gains included in earnings relating to derivatives still held as of June 30	$	32,189	$	(590)	$	(27,843)	$	1,544