Pension and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 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 June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
	(In thousands)
Defined Benefit Pension Plans
Service cost	$	273		$	251		$	545		$	501
Interest cost	1,332			1,312			2,664			2,624
Expected return on plan assets	(2,161		)	(2,079		)	(4,322		)	(4,157		)
Amortization of prior service credit	(1		)	(1		)	(2		)	(1		)
Amortization of unrecognized net loss	1,056			569			2,112			1,138
Net periodic benefit cost	$	499		$	52		$	997		$	105
Postretirement Benefit Plan
Service cost	$	4		$	4		$	8		$	9
Interest cost	33			36			67			71
Amortization of prior service cost	32			33			65			65
Amortization of unrecognized net gain	—			(26		)	(1		)	(52		)
Net periodic benefit cost	$	69		$	47		$	139		$	93