Restructuring and Related Costs (Summary Of Severance Charges On Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	$ 3,414	$ 3,962
Employee Severance
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	3,414	3,962
Employee Severance | Accrued payroll and related costs
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	2,914	3,485
Employee Severance | Other accrued liabilities
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	218	98
Employee Severance | Other long-term liabilities
Restructuring Cost and Reserve [Line Items]
Total severance and related costs	$ 282	$ 379