Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Nov. 30, 2023	Nov. 30, 2022
Qualified Pension Benefits
Component of net periodic benefit costs: [Abstract]
Service cost	$ 9,348	$ 9,645
Interest cost	8,982	7,647
Expected return on assets	(11,965)	(10,782)
Prior service cost (credit) amortization	45	37
Actuarial loss (gain) amortization	449	468
Net periodic benefit cost (benefit)	6,859	7,015
Non-Qualified Pension Benefits
Component of net periodic benefit costs: [Abstract]
Service cost	492	460
Interest cost	261	185
Expected return on assets	0	0
Prior service cost (credit) amortization	(29)	(29)
Actuarial loss (gain) amortization	95	61
Net periodic benefit cost (benefit)	819	677
Other Benefits
Component of net periodic benefit costs: [Abstract]
Service cost	163	168
Interest cost	286	259
Expected return on assets	0	0
Prior service cost (credit) amortization	(111)	(111)
Actuarial loss (gain) amortization	(404)	(404)
Net periodic benefit cost (benefit)	$ (66)	$ (88)