Derivative instruments (Tables)

12 Months Ended

Dec. 31, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of derivative instruments, gain (losses)

The gains and losses on derivative instruments for the years ended December 31 were as follows:

	2014		2013			2012
			(In thousands)
Commodity derivatives designated as cash flow hedges:
Amount of gain (loss) recognized in accumulated other comprehensive loss (effective portion), net of tax	$	—	$	(6,153	)	$	10,209
Amount of (gain) loss reclassified from accumulated other comprehensive loss into operating revenues (effective portion), net of tax	295		(4,916		)	(8,788		)
Amount of loss recognized in operating revenues (ineffective portion), before tax	—		(1,422		)	(730		)
Interest rate derivatives designated as cash flow hedges:
Amount of gain (loss) recognized in accumulated other comprehensive loss (effective portion), net of tax	—		559			(1,712		)
Amount of loss reclassified from accumulated other comprehensive loss into interest expense (effective portion), net of tax	399		727			34
Amount of loss recognized in interest expense (ineffective portion), before tax	—		(769		)	—
Commodity derivatives not designated as hedging instruments:
Amount of gain (loss) recognized in operating revenues, before tax	23,400		(4,845		)	106

Derivative instruments

The location and fair value of the Company's derivative instruments on the Consolidated Balance Sheets were as follows:

Asset Derivatives	Location on Consolidated Balance Sheets	Fair Value at December 31, 2014		Fair Value at December 31, 2013
		(In thousands)
Not designated as hedges:
Commodity derivatives	Commodity derivative instruments	$	18,335	$	1,447
	Other assets - noncurrent	—		503
Total asset derivatives		$	18,335	$	1,950

Liability Derivatives	Location on Consolidated Balance Sheets	Fair Value at December 31, 2014		Fair Value at December 31, 2013
		(In thousands)
Not designated as hedges:
Commodity derivatives	Commodity derivative instruments	$	—	$	7,483
Total liability derivatives		$	—	$	7,483

Offsetting assets and liabilities master netting

The gross derivative assets and liabilities (excluding settlement receivables and payables that may be subject to the same master netting agreements) presented on the Consolidated Balance Sheets and the amount eligible for offset under the master netting agreements is presented in the following table:

December 31, 2014	Gross Amounts Recognized on the Consolidated Balance Sheets		Gross Amounts Not Offset on the Consolidated Balance Sheets		Net
	(In thousands)
Assets:
Commodity derivatives	$	18,335	$	—	$	18,335
Total assets	$	18,335	$	—	$	18,335

December 31, 2013	Gross Amounts Recognized on the Consolidated Balance Sheets		Gross Amounts Not Offset on the Consolidated Balance Sheets			Net
	(In thousands)
Assets:
Commodity derivatives	$	1,950	$	(1,950	)	$	—
Total assets	$	1,950	$	(1,950	)	$	—
Liabilities:
Commodity derivatives	$	7,483	$	(1,950	)	$	5,533
Total liabilities	$	7,483	$	(1,950	)	$	5,533