Pension and Other Postretirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2013

Compensation and Retirement Disclosure [Abstract]

Components of net periodic benefit cost (income) for the Corporation's qualified and nonqualified pension plans and nonqualified postretirement benefits plan

The components of net periodic benefit cost (income) for the Corporation’s qualified and nonqualified pension plans and nonqualified postretirement benefit plan are as follows:

	Three Months Ended March 31,
	2013			2012
	(In thousands)
Defined Benefit Pension Plans
Service cost	$	325		$	303
Interest cost	1,167			1,215
Expected return on plan assets	(1,948		)	(1,731		)
Amortization of unrecognized net loss	946			614
Net periodic benefit cost	$	490		$	401
Postretirement Benefit Plan
Interest cost	$	75		$	37
Amortization of prior service credit	—			(75		)
Amortization of unrecognized net gain	—			(7		)
Net periodic benefit cost (income)	$	75		$	(45	)