EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Sep. 30, 2019

Retirement Benefits [Abstract]

Summary of Changes in Funded Status of Plans and Liabilities Recognized

The following summarizes the changes in the funded status of the plans and the related liabilities recognized on the Consolidated Balance Sheets as of September 30:

	Pension (1)						OPEB
(Thousands)	2019			2018			2019			2018
Change in Benefit Obligation
Benefit obligation at beginning of year	$	298,575		$	297,835		$	196,785		$	175,090
Service cost	7,381			8,139			4,404			4,607
Interest cost	12,173			10,493			8,324			6,365
Plan participants’ contributions (2)	43			45			210			161
Special termination benefits (3)	—			3,730			—			490
Actuarial loss (gain)	52,549			(12,846		)	54,700			15,145
Benefits paid, net of retiree subsidies received	(10,244		)	(8,821		)	(4,420		)	(5,073		)
Benefit obligation at end of year	$	360,477		$	298,575		$	260,003		$	196,785
Change in plan assets
Fair value of plan assets at beginning of year	$	279,410		$	271,743		$	77,980		$	71,534
Actual return on plan assets	19,194			16,306			2,499			5,284
Employer contributions	231			137			7,926			6,222
Benefits paid, net of plan participants’ contributions (2)	(10,201		)	(8,776		)	(4,479		)	(5,060		)
Fair value of plan assets at end of year	$	288,634		$	279,410		$	83,926		$	77,980
Funded status	$	(71,843	)	$	(19,165	)	$	(176,077	)	$	(118,805	)
Amounts recognized on Consolidated Balance Sheets
Postemployment employee (liability)
Current	$	(603	)	$	(294	)	$	(800	)	$	(669	)
Noncurrent	(71,240		)	(18,871		)	(175,277		)	(118,136		)
Total	$	(71,843	)	$	(19,165	)	$	(176,077	)	$	(118,805	)

(1) Includes the Company’s PEP.

(2) Prior to July 1, 1998, employees were eligible to elect an additional participant contribution to enhance their benefits and contributions made during the periods were insignificant.

(3) Related to the voluntary early retirement program offered during fiscal 2018, as previously discussed.

Summary of Regulatory Assets and Accumulated Other Comprehensive Income

The following table summarizes the amounts recognized in regulatory assets and accumulated other comprehensive income as of September 30:

	Regulatory Assets						Accumulated Other Comprehensive Income (Loss)
	Pension			OPEB			Pension			OPEB
Balance at September 30, 2017	$	78,605		$	60,460		$	19,415		$	4,967
Amounts arising during the period:
Net actuarial (gain) loss	(6,090		)	12,378			(3,422		)	2,834
Amounts amortized to net periodic costs:
Net actuarial (loss)	(6,177		)	(4,464		)	(1,359		)	(196		)
Prior service (cost) credit	(105		)	311			(1		)	54
Balance at September 30, 2018	$	66,233		$	68,685		$	14,633		$	7,659
Amounts arising during the period:
Net actuarial loss	38,137			48,452			14,271			9,264
Amounts amortized to net periodic costs:
Net actuarial (loss)	(4,662		)	(5,820		)	(1,103		)	(648		)
Prior service (cost) credit	(102		)	312			—			53
Balance at September 30, 2019	$	99,606		$	111,629		$	27,801		$	16,328

The amounts in regulatory assets and accumulated other comprehensive income not yet recognized as components of net periodic benefit cost as of September 30 are:

	Regulatory Assets										Accumulated Other Comprehensive Income (Loss)
	Pension				OPEB						Pension				OPEB
(Thousands)	2019		2018		2019			2018			2019		2018		2019			2018
Net actuarial loss	$	99,139	$	65,664	$	112,109		$	69,477		$	27,801	$	14,633	$	16,367		$	7,750
Prior service cost (credit)	467		569		(480		)	(792		)	—		—		(39		)	(91		)
Total	$	99,606	$	66,233	$	111,629		$	68,685		$	27,801	$	14,633	$	16,328		$	7,659

Schedule of Amounts Expected to be Recognized as Components of Net Periodic Benefit Cost

Amounts included in regulatory assets and accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost in fiscal 2020 are as follows:

	Regulatory Assets					Accumulated Other Comprehensive Income (Loss)
(Thousands)	Pension		OPEB			Pension		OPEB
Net actuarial loss	$	8,470	$	10,055		$	2,514	$	1,407
Prior service cost (credit)	102		(182		)	—		(15		)
Total	$	8,572	$	9,873		$	2,514	$	1,392

Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets

The accumulated benefit obligation for the pension plans, including the PEP, exceeded the fair value of plan assets. The projected benefit and accumulated benefit obligations and the fair value of plan assets as of September 30, are as follows:

	Pension
(Thousands)	2019		2018
Projected benefit obligation	$	360,477	$	298,575
Accumulated benefit obligation	$	319,527	$	263,279
Fair value of plan assets	$	288,634	$	279,410

Components of Net Periodic Cost

The components of the net periodic cost for pension benefits, including the Company’s PEP, and OPEB costs (principally health care and life insurance) for employees and covered dependents for fiscal years ended September 30, are as follows:

	Pension									OPEB
(Thousands)	2019			2018			2017			2019			2018			2017
Service cost	$	7,381		$	8,139		$	8,347		$	4,404		$	4,607		$	4,380
Interest cost	12,173			10,493			9,771			8,324			6,365			5,545
Expected return on plan assets	(19,054		)	(19,639		)	(19,313		)	(5,515		)	(5,352		)	(4,767		)
Recognized actuarial loss	5,765			7,537			8,827			6,466			4,660			4,370
Prior service cost (credit) amortization	102			106			111			(365		)	(365		)	(365		)
Net periodic benefit cost	$	6,367		$	6,636		$	7,743		$	13,314		$	9,915		$	9,163
Special termination benefit	—			3,730			—			—			490			—
Net periodic benefit cost recognized as expense	$	6,367		$	10,366		$	7,743		$	13,314		$	10,405		$	9,163

Schedule of Weighted Average Assumptions Used

The weighted average assumptions used to determine the Company’s benefit costs during the fiscal years below and obligations as of September 30, are as follows:

	Pension									OPEB
	2019			2018			2017			2019			2018			2017
Benefit costs:
Discount rate	4.36/4.35%		(1)	4.04/4.03%		(1)	3.96/3.94%		(1)	4.38/4.37%		(1)	4.12/4.08%		(1)	4.08/4.01%		(1)
Expected asset return	7.00	%		7.50	%		7.75	%		7.00	%		7.50	%		7.75	%
Compensation increase	3.25/3.50%		(1)	3.25/3.50%		(1)	3.25/3.50%		(1)	3.25/3.50		(1)	3.25/3.50%		(1)	3.25/3.50%		(1)
Obligations:
Discount rate	3.37/3.35%		(1)	4.36/4.35%		(1)	4.03	%		3.48/3.44%		(1)	4.38/4.37%		(1)	4.12/4.08%		(1)
Compensation increase	3.00/3.50%		(1)	3.25/3.50%		(1)	3.25/3.50%		(1)	3.00/3.50%		(1)	3.25/3.50%		(1)	3.25/3.50%		(1)

(1) Percentages for represented and nonrepresented plans, respectively.

Information on Assumed HCCTR Used to Determine Expected OPEB Benefits

Information relating to the assumed HCCTR used to determine expected OPEB benefits as of September 30, and the effect of a 1 percent change in the rate, are as follows:

($ in thousands)	2019			2018			2017
HCCTR	7.6%			7.9%			8.3%
Ultimate HCCTR	4.5%			4.5%			4.5%
Year ultimate HCCTR reached	2026			2024			2025
Effect of a 1 percentage point increase in the HCCTR on:
Year-end benefit obligation	$	49,061		$	36,260		$	32,019
Total service and interest cost	$	2,923		$	2,482		$	2,468
Effect of a 1 percentage point decrease in the HCCTR on:
Year-end benefit obligation	$	(38,747	)	$	(28,743	)	$	(25,466	)
Total service and interest costs	$	(2,250	)	$	(1,937	)	$	(1,909	)

Schedule of Mix and Targeted Allocation of Plan Assets

The mix and targeted allocation of the pension and OPEB plans’ assets are as follows:

	2020		Assets at
	Target		September 30,
Asset Allocation	Allocation		2019		2018
U.S. equity securities	34	%	37	%	41	%
International equity securities	17		17		19
Fixed income	38		42		37
Other assets	11		4		3
Total	100	%	100	%	100	%

Schedule of Expected Benefit Payments

The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid during the following fiscal years:

(Thousands)	Pension		OPEB
2020	$	12,234	$	6,267
2021	$	12,758	$	6,804
2022	$	13,585	$	7,589
2023	$	14,405	$	8,249
2024	$	15,210	$	8,910
2025 - 2029	$	90,726	$	55,025

Schedule of Estimated Subsidy Payments

The following estimated subsidy payments are expected to be paid during the following fiscal years:

	Estimated Subsidy
(Thousands)	Payment
2020		$	261
2021		$	286
2022		$	314
2023		$	350
2024		$	387
2025 - 2029		$	2,605

Summary of Pension and OPEB Assets Held in the Master Trust

Pension and OPEB assets held in the master trust, measured at fair value, as of September 30, are summarized as follows:

(Thousands)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Total
As of September 30, 2019:	Pension				OPEB
Assets
Money market funds	$	—	$	—	$	21	$	21
Registered Investment Companies:
Equity Funds:
Large Cap Index	89,374		89,374		25,474		25,474
Extended Market Index	16,548		16,548		5,036		5,036
International Stock	49,929		49,929		14,564		14,564
Fixed Income Funds:
Emerging Markets	15,794		15,794		4,764		4,764
Core Fixed Income	—		—		10,570		10,570
Opportunistic Income	—		—		6,365		6,365
Ultra Short Duration	—		—		6,340		6,340
High Yield Bond Fund	24,328		24,328		7,350		7,350
Long Duration Fund	80,041		80,041		—		—
Total assets at in the fair value hierarchy	$	276,014	276,014		$	80,484	80,484
Investments measured at net asset value
Common collective trusts			12,620				3,442
Total assets at fair value			$	288,634			$	83,926

(Thousands)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Total
As of September 30, 2018:	Pension				OPEB
Assets
Money market funds	$	8,207	$	8,207	$	2,273	$	2,273
Registered Investment Companies:
Equity Funds:
Large Cap Index	97,016		97,016		27,340		27,340
Extended Market Index	17,741		17,741		5,014		5,014
International Stock	53,516		53,516		14,874		14,874
Fixed Income Funds:
Emerging Markets	11,754		11,754		3,264		3,264
Core Fixed Income	—		—		7,970		7,970
Opportunistic Income	—		—		4,798		4,798
Ultra Short Duration	—		—		4,830		4,830
High Yield Bond Fund	25,720		25,720		7,236		7,236
Long Duration Fund	64,039		64,039		—		—
Total assets at in the fair value hierarchy	$	277,993	277,993		$	77,599	77,599
Investments measured at net asset value
Common collective trusts			1,417				381
Total assets at fair value			$	279,410			$	77,980