Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Disclosures [Abstract]

Fair value hierarchy for financial instruments measured at fair value on a recurring basis

The fair value hierarchy for our financial assets and liabilities is shown by the following table:

	As of June 30, 2014									As of December 31, 2013
	Derivative assets			Derivative liabilities			Net assets (liabilities)			Derivative assets			Derivative liabilities			Net assets (liabilities)
Significant other observable inputs (Level 2)	$	1,150		$	(9,870	)	$	(8,720	)	$	3,275		$	(6,576	)	$	(3,301	)
Significant unobservable inputs (Level 3)	414			(55,366		)	(54,952		)	9,838			(6,216		)	3,622
Netting adjustments (1)	(1,261		)	1,261			—			(4,558		)	4,558			—
	$	303		$	(63,975	)	$	(63,672	)	$	8,555		$	(8,234	)	$	321

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(1) Amounts represent the impact of master netting agreements that allow us to net settle positive and negative positions with the same counterparty. Positive and negative positions with a counterparty are netted on the balance sheet only to the extent that they relate to the same current versus noncurrent classification.

Level 3 rollforward

Changes in the fair value of our derivative instruments classified as Level 3 in the fair value hierarchy during the six months ended June 30, 2014 and 2013 were: 

	Six months ended June 30,
Net derivative assets (liabilities)	2014			2013
Beginning balance	$	3,622		$	26,231
Realized and unrealized losses included in non-hedge derivative losses	(70,048		)	15,614
Purchases	1,220			664
Settlements paid (received)	10,254			(11,556		)
Ending balance	$	(54,952	)	$	30,953
(Losses) gains relating to instruments still held at the reporting date included in non-hedge derivative (losses) gains for the period	$	(63,617	)	$	18,651

Fair value of other financial instruments

The carrying value and estimated fair value of our long-term debt at June 30, 2014 and December 31, 2013 were as follows:

	June 30, 2014				December 31, 2013
Level 2	Carrying value		Estimated fair value		Carrying value		Estimated fair value
9.875% Senior Notes due 2020	$	294,839	$	339,750	$	294,556	$	340,140
8.25% Senior Notes due 2021	400,000		442,000		400,000		437,000
7.625% Senior Notes due 2022	555,286		598,098		555,719		583,275
Senior secured revolving credit facility	249,000		249,000		272,000		272,000
Other secured long-term debt	16,038		16,038		16,437		16,437
	$	1,515,163	$	1,644,886	$	1,538,712	$	1,648,852

Offsetting Assets and Liabilities

The following table summarizes our derivative assets and liabilities which are offset in the consolidated balance sheets under our master netting agreements. It also reflects the amounts outstanding under our senior secured revolving credit facility that are available to offset our net derivative assets due from counterparties that are lenders under our senior secured revolving credit facility.

	Offset in the consolidated balance sheets									Gross amounts not offset in the consolidated balance sheets
	Gross assets (liabilities)			Offsetting assets (liabilities)			Net assets (liabilities)			Derivatives(1)			Amounts outstanding under senior secured revolving credit facility			Net amount
As of June 30, 2014
Derivative assets	$	1,564		$	(1,261	)	$	303		$	(303	)	$	—		$	—
Derivative liabilities	(65,236		)	1,261			(63,975		)	303			—			(63,672		)
	$	(63,672	)	$	—		$	(63,672	)	$	—		$	—		$	(63,672	)
As of December 31, 2013
Derivative assets	$	13,113		$	(4,558	)	$	8,555		$	(3,484	)	$	(4,211	)	$	860
Derivative liabilities	(12,792		)	4,558			(8,234		)	3,484			—			(4,750		)
	$	321		$	—		$	321		$	—		$	(4,211	)	$	(3,890	)

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(1) Since positive and negative positions with a counterparty are netted on the balance sheet only to the extent that they relate to the same current versus noncurrent classification, these represent remaining amounts that could have been offset under our master netting agreements.