EMPLOYEE BENEFIT PLANS (Tables)

9 Months Ended

Jun. 30, 2019

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						Nine Months Ended						Three Months Ended						Nine Months Ended
	June 30,						June 30,						June 30,						June 30,
(Thousands)	2019			2018			2019			2018			2019			2018			2019			2018
Service cost	$	1,845		$	2,035		$	5,536		$	6,104		$	1,101		$	1,152		$	3,303		$	3,455
Interest cost	3,043			2,623			9,129			7,870			2,081			1,591			6,243			4,773
Expected return on plan assets	(4,763		)	(4,910		)	(14,290		)	(14,729		)	(1,379		)	(1,338		)	(4,137		)	(4,014		)
Recognized actuarial loss	1,442			1,884			4,324			5,653			1,617			1,165			4,850			3,495
Prior service cost amortization	25			27			76			80			(91		)	(91		)	(273		)	(273		)
Net periodic benefit cost	$	1,592		$	1,659		$	4,775		$	4,978		$	3,329		$	2,479		$	9,986		$	7,436