Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Fair Value Measurements [Abstract]

Carrying Amount and Estimated Fair Values of Financial Instruments

	June 30,				December 31,
	2012				2011
	Carrying		Fair		Carrying		Fair
	Amount		Value		Amount		Value
	(in thousands)
Cash and cash equivalents	$	41,499	$	41,499	$	15,627	$	15,627
Restricted cash	$	144,384	$	144,384	$	–	$	–
Unsecured revolving credit facility	$	–	$	–	$	671,500	$	671,500
Senior notes	$	1,670,011	$	1,852,847	$	671,800	$	773,578
Derivative instruments	$	564,707	$	564,707	$	704,830	$	704,830

Summary Assets and Liabilities Measured at Fair Value on Recurring Basis

	June 30, 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	$	–	$	465,571	$	106,391	$	571,962
Derivative liabilities		–		(7,086)		(169)		(7,255)
Total	$	–	$	458,485	$	106,222	$	564,707
	December 31, 2011
	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	$	–	$	534,560	$	182,783	$	717,343
Derivative liabilities		–		(11,849)		(664)		(12,513)
Total	$	–	$	522,711	$	182,119	$	704,830

Assets 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,
	2012		2011		2012		2011
	(in thousands)
Balance at beginning of period	$	184,543	$	85,580	$	182,119	$	97,677
Total gains or losses (realized/unrealized):
Included in earnings		65,274		11,682		123,736		27,592
Included in other comprehensive income		(77,731)		3,996		(77,441)		(11,310)
Purchases, issuances, and settlements:
Purchases		–		–		–		–
Issuances		–		–		–		–
Settlements		(65,864)		(11,863)		(122,192)		(24,706)
Transfers into/out of Level 3		–		–		–		142
Balance at end of period	$	106,222	$	89,395	$	106,222	$	89,395
Change in unrealized gains included in earnings relating to derivatives still held as of June 30	$	(590)	$	(181)	$	1,544	$	2,886