Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

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 December 31, 2017 and 2016.



	Fair value measurements at December 31, 2017 using:
In thousands	Level 1		Level 2		Level 3		Total
Derivative assets:
Swaps	$	—	$	2,603	$	—	$	2,603
Total	$	—	$	2,603	$	—	$	2,603



	Fair value measurements at December 31, 2016 using:
In thousands	Level 1		Level 2			Level 3		Total
Derivative liabilities:
Swaps	$	—	$	(12,297	)	$	—	$	(12,297	)
Collars	—		(43,131		)	—		(43,131		)
Total	$	—	$	(55,428	)	$	—	$	(55,428	)

Unobservable inputs used in level 3 fair value measurements



Unobservable Input		Assumption
Future production		Future production estimates for each property
Forward commodity prices		Forward NYMEX strip prices through 2022 (adjusted for differentials), escalating 3% per year thereafter
Operating costs		Estimated costs for the current year, escalating 3% per year thereafter
Productive life of field		Ranging from 1 to 38 years
Discount rate		10%

Unobservable inputs to the fair value assessment are reviewed quarterly and are revised as warranted based on a number of factors, including reservoir performance, new drilling, crude oil and natural gas prices, changes in costs, technological advances, new geological or geophysical data, or other economic factors. Fair value measurements of proved properties are reviewed and approved by certain members of the Company’s management.

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 consolidated statements of comprehensive income (loss).



	Year ended December 31,
In thousands	2017		2016		2015
Proved property impairments	$	82,340	$	2,895	$	138,878
Unproved property impairments	155,030		234,397		263,253
Total	$	237,370	$	237,292	$	402,131

Fair Values of Financial Instruments not Recorded at Fair Value

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



	December 31, 2017				December 31, 2016
In thousands	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Debt:
Revolving credit facility (1)	$	188,000	$	188,000	$	905,000	$	905,000
Term loan (1)	—		—		498,865		500,000
Note payable	9,974		9,900		12,176		10,200
5% Senior Notes due 2022	1,997,576		2,040,000		1,997,188		2,020,400
4.5% Senior Notes due 2023	1,486,690		1,526,800		1,484,524		1,474,800
3.8% Senior Notes due 2024	992,036		988,800		990,964		929,400
4.375% Senior Notes due 2028 (1)	988,061		987,200		—		—
4.9% Senior Notes due 2044	691,354		679,900		691,199		607,600
Total debt	$	6,353,691	$	6,420,600	$	6,579,916	$	6,447,400

(1) In December 2017, the Company issued $1.0 billion of 4.375% Senior Notes due 2028 and used the proceeds therefrom to repay in full and terminate its term loan and to repay a portion of the borrowings outstanding under its revolving credit facility. See Note 7. Long-Term Debt for further discussion.