PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Tables)

9 Months Ended

Sep. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Components of net periodic benefit cost for RIGP and Retiree Medical Plan

The components of the net periodic benefit cost for the RIGP and Retiree Medical Plan were as follows for the three and nine months ended September 30, 2016 and 2015 (in thousands):

	RIGP						Retiree Medical Plan
	Three Months Ended   September 30,						Three Months Ended   September 30,
	2016			2015			2016		2015
Service cost	$	(9	)	$	3		$	81	$	92
Interest cost	106			137			327		333
Expected return on plan assets	(64		)	(84		)	—		—
Amortization of unrecognized losses	130			211			—		50
Actuarial loss due to settlements	122			451			—		—
Net periodic benefit cost	$	285		$	718		$	408	$	475

	RIGP						Retiree Medical Plan
	Nine Months Ended   September 30,						Nine Months Ended   September 30,
	2016			2015			2016		2015
Service cost	$	(26	)	$	9		$	242	$	274
Interest cost	316			413			982		1,000
Expected return on plan assets	(192		)	(251		)	—		—
Amortization of unrecognized losses	391			632			—		149
Actuarial loss due to settlements	365			451			—		—
Net periodic benefit cost	$	854		$	1,254		$	1,224	$	1,423