Retirement and Other Benefit Plans - Schedule Of Funded Status (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Retirement and Other Benefit Plans
Funded status at end of year	$ (2,800)	$ (22,900)
Accrued benefit cost	(2,800)	(22,900)
Current liability	(300)	(200)
Noncurrent liability	(2,481)	(22,682)
Accumulated other comprehensive (income)/loss (before tax effect)	700	49,600
Net actuarial loss	700	49,600
Accumulated other comprehensive (income)/loss (before tax effect)	$ 700	$ 49,600