Pension Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss expected to be recognized in the following year		$ 3,800
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		3,500	$ 1,000	$ 6,300
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 2,600	$ 2,500	$ 2,000
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans, vesting period		1 year
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans, vesting period		5 years
Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic pension cost	$ 1,900
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average assumptions used to determine net periodic pension cost for fiscal years ended September 30, Rate of return on plan assets		5.40%	5.40%	5.40%
Net periodic pension cost		$ 1,198	$ 912	$ 2,564
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)		3,512	1,025
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 2,576	$ 2,459
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Current asset allocation target for fixed income securities		100.00%