Restructuring And Related Cost (Restructuring Reserve) (Details) - USD ($)	12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 3,962,000	$ 2,296,000
Restructuring expense	2,730,000	4,079,000	$ 2,165,000
Payments	(2,399,000)	(2,307,000)
Other adjustments	98,000	(23,000)
Currency translation	0	(83,000)
Restructuring reserve, ending balance	4,391,000	3,962,000	2,296,000
2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0	308,000
Restructuring expense	0	0
Payments	0	(303,000)
Other adjustments	0	0
Currency translation	0	(5,000)
Restructuring reserve, ending balance	0	0	308,000
2014 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	0	0	0
Test [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	2,699,000	2,922,000	847,000
Test [Member] | 2018 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0	0
Restructuring expense	880,000	0
Payments	(67,000)	0
Other adjustments	238,000	0
Currency translation	0	0
Restructuring reserve, ending balance	1,051,000	0	0
Test [Member] | 2017 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	2,899,000	0
Restructuring expense	1,819,000	2,922,000
Payments	(1,748,000)	0
Other adjustments	(37,000)	(23,000)
Currency translation	0	0
Restructuring reserve, ending balance	2,933,000	2,899,000	0
Test [Member] | 2014 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	734,000	1,053,000
Restructuring expense	0	0
Payments	(386,000)	(352,000)
Other adjustments	3,000	0
Currency translation	(1,000)	33,000
Restructuring reserve, ending balance	350,000	734,000	1,053,000
Sensors [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	31,000	1,157,000	1,318,000
Sensors [Member] | 2017 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	120,000	0
Restructuring expense	31,000	121,000
Payments	(92,000)	0
Other adjustments	0	0
Currency translation	(2,000)	(1,000)
Restructuring reserve, ending balance	57,000	120,000	0
Sensors [Member] | 2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	209,000	935,000
Restructuring expense	0	1,036,000
Payments	(106,000)	(1,652,000)
Other adjustments	(106,000)	0
Currency translation	3,000	(110,000)
Restructuring reserve, ending balance	$ 0	$ 209,000	$ 935,000