Employee benefit plans (Tables)

6 Months Ended

Jun. 30, 2014

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of net benefit costs

Components of net periodic benefit cost for the Company's pension and other postretirement benefit plans were as follows:

							Other
							Postretirement
	Pension Benefits						Benefits
Three Months Ended June 30,	2014			2013			2014			2013
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	31		$	37		$	380		$	334
Interest cost	4,405			4,106			924			667
Expected return on assets	(5,484		)	(4,875		)	(1,242		)	(1,065		)
Amortization of prior service cost (credit)	18			18			(348		)	(364		)
Amortization of net actuarial loss	1,121			1,716			6			407
Net periodic benefit cost, including amount capitalized	91			1,002			(280		)	(21		)
Less amount capitalized	73			158			(19		)	61
Net periodic benefit cost (credit)	$	18		$	844		$	(261	)	$	(82	)

							Other
							Postretirement
	Pension Benefits						Benefits
Six Months Ended June 30,	2014			2013			2014			2013
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	64		$	77		$	759		$	838
Interest cost	8,845			8,124			1,782			1,607
Expected return on assets	(10,609		)	(9,958		)	(2,309		)	(2,172		)
Amortization of prior service cost (credit)	36			36			(696		)	(728		)
Amortization of net actuarial loss	2,434			3,580			324			1,078
Net periodic benefit cost, including amount capitalized	770			1,859			(140		)	623
Less amount capitalized	168			268			10			90
Net periodic benefit cost (credit)	$	602		$	1,591		$	(150	)	$	533