Restructuring And Related Costs (Summary Of Severance Charges On Statement Of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 2,730	$ 4,079	$ 2,165
Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,622	3,140	1,061
Selling and Marketing Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	267	315	284
General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	317	624	815
Research and Development Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	524	0	5
Test [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	2,699	2,922	847
Test [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,622	2,439	299
Test [Member] | Selling and Marketing Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	236	112	129
Test [Member] | General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	317	371	414
Test [Member] | Research and Development Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	524	0	5
Sensors [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	31	1,157	1,318
Sensors [Member] | Cost of Sales [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	0	701	762
Sensors [Member] | Selling and Marketing Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	31	203	155
Sensors [Member] | General and Administrative Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	0	253	401
Sensors [Member] | Research and Development Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 0	$ 0	$ 0