EMPLOYEE BENEFITS - POSTRETIREMENT (Tables)

3 Months Ended

Mar. 31, 2017

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of Net Periodic Benefit Costs Charged to Operating Expenses

The net periodic benefit costs charged to operating expenses, which are valued at the measurement date of January 1 and recognized evenly throughout the year, consisted of the following components (in thousands of dollars):

	Three Months Ended March 31,
	2017			2016
Service cost	$	1,897		$	2,059
Interest cost	2,149			2,464
Expected return on assets	(2,857		)	(2,528		)
Amortization of unrecognized losses	(655		)	32
Amortization of prior service credits	(1,622		)	(1,672		)
Net periodic benefit costs	$	(1,088	)	$	355