Business Segment Information (Financial Information By Reportable Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Sep. 27, 2014
Segment Reporting Information [Line Items]
Revenue	$ 650,147	$ 563,934	$ 564,328
Income from Operations	41,763	61,496	60,256
Identifiable Assets	1,188,020	460,831	487,408
Goodwill	369,700	27,677	26,123
Capital Expenditures	20,806	18,445	20,038
Depreciation and Amortization	24,077	21,106	19,279
Test [Member]
Segment Reporting Information [Line Items]
Revenue	512,265	462,880	458,153
Income from Operations	40,660	42,285	39,848
Identifiable Assets	395,067	369,515	392,825
Goodwill	25,022	26,243	24,584
Capital Expenditures	17,570	14,652	16,553
Depreciation and Amortization	17,279	18,342	16,560
Sensors [Member]
Segment Reporting Information [Line Items]
Revenue	137,882	101,054	106,175
Income from Operations	1,103	19,211	20,408
Identifiable Assets	792,953	91,316	94,583
Goodwill	344,678	1,434	1,539
Capital Expenditures	3,236	3,793	3,485
Depreciation and Amortization	$ 6,798	$ 2,764	$ 2,719