Employee benefit plans (Tables)

6 Months Ended

Jun. 30, 2013

Employee Benefit Plans [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,	2013			2012			2013			2012
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	37		$	350		$	334		$	461
Interest cost	4,106			4,262			667			1,038
Expected return on assets	(4,875		)	(5,845		)	(1,065		)	(1,201		)
Amortization of prior service cost (credit)	18			(21		)	(364		)	(272		)
Amortization of net actuarial loss	1,716			2,102			407			887
Amortization of net transition obligation	—			—			—			531
Net periodic benefit cost, including amount capitalized	1,002			848			(21		)	1,444
Less amount capitalized	158			196			61			183
Net periodic benefit cost (credit)	$	844		$	652		$	(82	)	$	1,261
							Other
							Postretirement
	Pension Benefits						Benefits
Six Months Ended June 30,	2013			2012			2013			2012
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	77		$	695		$	838		$	873
Interest cost	8,124			8,816			1,607			2,181
Expected return on assets	(9,958		)	(11,731		)	(2,172		)	(2,445		)
Amortization of prior service cost (credit)	36			(42		)	(728		)	(544		)
Amortization of net actuarial loss	3,580			3,783			1,078			1,413
Amortization of net transition obligation	—			—			—			1,063
Net periodic benefit cost, including amount capitalized	1,859			1,521			623			2,541
Less amount capitalized	268			430			90			321
Net periodic benefit cost	$	1,591		$	1,091		$	533		$	2,220