Pension and other postretirement benefits (Tables)

3 Months Ended

Mar. 31, 2013

Net Benefit Cost of Pension and Postretirement Benefit Plans

Net benefit cost of pension and postretirement benefit plans consisted of the following:

	Pension Three Months Ended						Other Postretirement Benefits Three Months Ended
	March 31, 2013			April 1, 2012			March 31, 2013		April 1, 2012
	(Dollars in thousands)
Service cost	$	465		$	678		$	164	$	158
Interest cost		4,139			4,126			999		473
Expected return on plan assets		(5,770	)		(5,043	)		—		—
Net amortization and deferral		1,410			1,606			730		123
Net benefit cost	$	244		$	1,367		$	1,893	$	754