RETIREMENT BENEFITS AND ASSETS HELD IN TRUST (Tables)

3 Months Ended

Mar. 31, 2016

Defined Benefit Plans

Defined Benefit Plan Disclosure

Schedule of Net Defined Benefit Cost Components

Net periodic benefit cost for the pension plans, by component, was as follows for the three months ended March 31, 2016 and 2015:

	Three months ended
	March 31,
(in thousands)	2016			2015
Service cost	$	1,604		$	1,624
Interest cost	872			924
Expected return on plan assets	(932		)	(960		)
Amortization of prior service credit	(4		)	(10		)
Amortization of unrecognized loss	876			1,061
Net pension cost	$	2,416		$	2,639

Other Postretirement Benefits Plan

Defined Benefit Plan Disclosure

Schedule of Net Defined Benefit Cost Components

Net postretirement benefit plan cost, by component, was as follows for the three months ended March 31, 2016 and 2015:

	Three months ended
	March 31,
(in thousands)	2016			2015
Service cost	$	1,855		$	2,122
Interest cost	630			619
Expected return on plan assets	(530		)	(463		)
Amortization of unrecognized loss	—			125
Net postretirement cost	$	1,955		$	2,403