Pension and Other Postretirement Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2015

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 for the Corporation’s qualified and nonqualified pension plans and nonqualified postretirement benefit plan are as follows:

	Three Months Ended March 31,
	2015			2014
	(In thousands)
Defined Benefit Pension Plans
Service cost	$	273		$	250
Interest cost	1,332			1,312
Expected return on plan assets	(2,161		)	(2,078		)
Amortization of prior service credit	(1		)	—
Amortization of unrecognized net loss	1,056			569
Net periodic benefit cost	$	499		$	53
Postretirement Benefit Plan
Service cost	$	4		$	5
Interest cost	33			35
Amortization of prior service cost	32			32
Amortization of unrecognized net gain	—			(26		)
Net periodic benefit cost	$	69		$	46