Restructuring And Related Cost (Restructuring Reserve) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015	Sep. 27, 2014
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 2,296,000	$ 1,548,000
Restructuring expense	4,079,000	2,165,000	$ 0
Payments	(2,307,000)	(1,736,000)
Other adjustments	(23,000)	336,000
Currency translation	(83,000)	(17,000)
Restructuring reserve, ending balance	3,962,000	2,296,000	1,548,000
2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	308,000	0
Restructuring expense	0	1,237,000
Payments	(303,000)	(1,238,000)
Other adjustments	0	336,000
Currency translation	(5,000)	(27,000)
Restructuring reserve, ending balance	0	308,000	0
2014 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	0	0	0	$ 6,336,000
Test [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	2,922,000	847,000
Test [Member] | 2017 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0	0
Restructuring expense	2,922,000	0
Payments	0	0
Other adjustments	(23,000)	0
Currency translation	0	0
Restructuring reserve, ending balance	2,899,000	0	0
Test [Member] | 2014 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	1,053,000	1,548,000
Restructuring expense	0	0
Payments	(352,000)	(498,000)
Other adjustments	0	0
Currency translation	33,000	3,000
Restructuring reserve, ending balance	734,000	1,053,000	1,548,000
Sensors [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	1,157,000	1,318,000
Sensors [Member] | 2017 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0	0
Restructuring expense	121,000	0
Payments	0	0
Other adjustments	0	0
Currency translation	(1,000)	0
Restructuring reserve, ending balance	120,000	0	0
Sensors [Member] | 2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	935,000	0
Restructuring expense	1,036,000	928,000
Payments	(1,652,000)	0
Other adjustments	0	0
Currency translation	(110,000)	7,000
Restructuring reserve, ending balance	$ 209,000	$ 935,000	$ 0