EMPLOYEE BENEFIT PLANS (Tables)

3 Months Ended

Dec. 31, 2017

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

The components of the net periodic cost for pension benefits, including the Company's Pension Equalization Plan, and OPEB costs (principally health care and life insurance) for employees and covered dependents were as follows:

	Pension						OPEB
	Three Months Ended						Three Months Ended
	December 31,						December 31,
(Thousands)	2017			2016			2017			2016
Service cost	$	2,035		$	2,087		$	1,152		$	1,095
Interest cost	2,623			2,443			1,591			1,386
Expected return on plan assets	(4,910		)	(4,828		)	(1,338		)	(1,192		)
Recognized actuarial loss	1,884			2,207			1,165			1,093
Prior service cost amortization	27			27			(91		)	(91		)
Net periodic benefit cost	$	1,659		$	1,936		$	2,479		$	2,291