Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

Valuation of Financial Instruments by Pricing Levels

The following tables summarize the valuation of financial instruments by pricing levels that were accounted for at fair value on a recurring basis as of September 30, 2014 and December 31, 2013.

	Fair value measurements at September 30, 2014 using:
In thousands	Level 1		Level 2			Level 3		Total
Derivative assets (liabilities):
Fixed price swaps	$	—	$	151,896		$	—	$	151,896
Collars	—		22,374			—		22,374
Total	$	—	$	174,270		$	—	$	174,270
	Fair value measurements at December 31, 2013 using:
In thousands	Level 1		Level 2			Level 3		Total
Derivative assets (liabilities):
Fixed price swaps	$	—	$	(84,893	)	$	—	$	(84,893	)
Collars	—		(9,855		)	—		(9,855		)
Total	$	—	$	(94,748	)	$	—	$	(94,748	)

Quantitative Information about Significant Unobservable Inputs

The following table sets forth quantitative information about the significant unobservable inputs used by the Company to calculate the fair value of proved crude oil and natural gas properties using a discounted cash flow method.

Unobservable Input	Assumption
Future production	Future production estimates for each property
Forward commodity prices	Forward NYMEX swap prices through 2018 (adjusted for differentials), escalating 3% per year thereafter
Operating and development costs	Estimated costs for the current year, escalating 3% per year thereafter
Productive life of field	Ranging from 0 to 50 years
Discount rate	10%

Property Impairments

The following table sets forth the non-cash impairments of both proved and unproved properties for the indicated periods. Proved and unproved property impairments are recorded under the caption “Property impairments” in the unaudited condensed consolidated statements of income.

	Three months ended September 30,				Nine months ended September 30,
In thousands	2014		2013		2014		2013
Proved property impairments	$	38,046	$	—	$	69,337	$	39,635
Unproved property impairments	47,515		42,167		153,748		122,325
Total	$	85,561	$	42,167	$	223,085	$	161,960

Fair Values of Financial Instruments not Recorded at Fair Value

The following table sets forth the fair values of financial instruments that are not recorded at fair value in the condensed consolidated financial statements.

	September 30, 2014				December 31, 2013
In thousands	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Debt:
Credit facility	$	—	$	—	$	275,000	$	275,000
Note payable	16,967		15,186		18,470		16,500
8.25% Senior Notes due 2019 (1)	—		—		298,305		327,800
7.375% Senior Notes due 2020	198,809		220,940		198,695		223,700
7.125% Senior Notes due 2021	400,000		443,240		400,000		450,300
5% Senior Notes due 2022	2,023,568		2,106,000		2,025,362		2,063,300
4.5% Senior Notes due 2023	1,500,000		1,560,000		1,500,000		1,519,400
3.8% Senior Notes due 2024	996,548		1,003,900		—		—
4.9% Senior Notes due 2044	698,030		728,350		—		—
Total debt	$	5,833,922	$	6,077,616	$	4,715,832	$	4,876,000

(1) These senior notes were redeemed in July 2014. See Note 6. Long-Term Debt for further discussion.