Accrued Liabilities (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2018
Restructuring Cost And Reserve [Line Items]
Restructuring charges	$ 22,216	$ 17,013
Termination Plan [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring and related charges	$ 23,673
Duarte Relocation Restructuring Charge Reserve
Restructuring Cost And Reserve [Line Items]
Restructuring charges		$ 17,013