EMPLOYEE BENEFIT PLANS (Tables)

3 Months Ended

Mar. 31, 2016

Compensation and Retirement Disclosure [Abstract]

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

The reconciliation of funded status for the Pension Plans and other postretirement benefit plans as of December 31, 2015 was as follows:



	Pension Plans			Other Postretirement Benefits
	(Thousands of Dollars)
Fair value of plan assets	$	87,706		$	—
Less: Benefit obligation	109,202			10,042
Funded status	$	(21,496	)	$	(10,042	)

Schedule of Net Benefit Costs [Table Text Block]

The following table summarizes the components of net periodic benefit costs for the Pension Plans and other postretirement benefits on a combined basis for periods prior to the Employee Transfer and after the Employee Transfer:



	Pension Plans						Other Postretirement Benefits
	2016			2015			2016			2015
	(Thousands of Dollars)
For the three months ended March 31:
Service cost	$	1,926		$	1,919		$	105		$	118
Interest cost	1,006			1,097			100			112
Expected return on assets	(1,352		)	(1,254		)	—			—
Amortization of prior service credit	(517		)	(516		)	(286		)	(286		)
Amortization of net loss	273			461			45			67
Net periodic benefit cost (income)	$	1,336		$	1,707		$	(36	)	$	11