Pension and Other Postretirement Benefit Plans (Tables)

9 Months Ended

Sep. 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 September 30,						Nine Months Ended September 30,
	2015			2014			2015			2014
	(In thousands)
Defined Benefit Pension Plans
Service cost	$	273		$	250		$	818		$	751
Interest cost	1,331			1,312			3,995			3,936
Expected return on plan assets	(2,161		)	(2,078		)	(6,483		)	(6,235		)
Amortization of prior service credit	(2		)	—			(4		)	(1		)
Amortization of unrecognized net loss	1,057			569			3,169			1,707
Net periodic benefit cost	$	498		$	53		$	1,495		$	158
Postretirement Benefit Plan
Service cost	$	4		$	5		$	12		$	14
Interest cost	33			36			100			107
Amortization of prior service cost	32			32			97			97
Amortization of unrecognized net gain	—			(26		)	(1		)	(78		)
Net periodic benefit cost	$	69		$	47		$	208		$	140