Restructuring and Related Costs (Summary Of Severance Charges On Balance Sheet) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	$ 3,231	$ 3,962
Employee Severance
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	3,231	3,962
Employee Severance | Accrued payroll and related costs
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	2,925	3,485
Employee Severance | Other accrued liabilities
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	103	98
Employee Severance | Other long-term liabilities
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	$ 203	$ 379