Employee benefit plans (Tables)

6 Months Ended

Jun. 30, 2012

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,	2012			2011			2012			2011
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	350		$	827		$	461		$	383
Interest cost	4,262			4,959			1,038			1,161
Expected return on assets	(5,845		)	(5,727		)	(1,201		)	(1,308		)
Amortization of prior service cost (credit)	(21		)	44			(272		)	(669		)
Amortization of net actuarial (gain) loss	2,102			1,049			887			(53		)
Amortization of net transition obligation	—			—			531			531
Curtailment loss	—			1,218			—			—
Net periodic benefit cost, including amount capitalized	848			2,370			1,444			45
Less amount capitalized	196			287			183			(28		)
Net periodic benefit cost	$	652		$	2,083		$	1,261		$	73
							Other
							Postretirement
	Pension Benefits						Benefits
Six Months Ended June 30,	2012			2011			2012			2011
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	695		$	1,654		$	873		$	722
Interest cost	8,816			9,919			2,181			2,350
Expected return on assets	(11,731		)	(11,427		)	(2,445		)	(2,526		)
Amortization of prior service cost (credit)	(42		)	87			(544		)	(1,338		)
Amortization of net actuarial loss	3,783			2,592			1,413			258
Amortization of net transition obligation	—			—			1,063			1,062
Curtailment loss	—			1,218			—			—
Net periodic benefit cost, including amount capitalized	1,521			4,043			2,541			528
Less amount capitalized	430			535			321			(95		)
Net periodic benefit cost	$	1,091		$	3,508		$	2,220		$	623