Benefit Plans - Components of Net Periodic Benefit Costs and Amounts Recognized in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
Aug. 31, 2026	Aug. 31, 2025	Aug. 31, 2024
Pension Benefits \| Qualified Pension Benefits
Other comprehensive loss (income):
Prior service cost	$ 357	$ (6,236)	$ 223
Net actuarial loss (gain)	7,186	22,472	23,309
Amortization of actuarial (gain) loss	(16,498)	(12,815)	(1,796)
Amortization of prior service (credit) costs	595	(199)	(178)
Total recognized in other comprehensive loss (income)	(8,360)	3,222	21,558
Pension Benefits \| Nonqualified Pension Benefits
Other comprehensive loss (income):
Prior service cost	0	(227)	0
Net actuarial loss (gain)	(1,388)	2,896	4,087
Amortization of actuarial (gain) loss	(982)	(799)	(380)
Amortization of prior service (credit) costs	30	47	114
Total recognized in other comprehensive loss (income)	(2,340)	1,917	3,821
Other Benefits
Other comprehensive loss (income):
Prior service cost	(2,424)	0	0
Net actuarial loss (gain)	(7)	(1,519)	2,145
Amortization of actuarial (gain) loss	1,197	1,192	1,616
Amortization of prior service (credit) costs	445	445	445
Total recognized in other comprehensive loss (income)	$ (789)	$ 118	$ 4,206

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- Definition

Amount, before tax, of cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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- Definition

Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount, before tax, after reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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