Summary Of Significant Accounting Policies (Narrative 1) (Details)	3 Months Ended	12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 29, 2018 USD ($) reporting_unit	Sep. 30, 2017 USD ($)	Oct. 01, 2016 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Maximum number of months for manufacturing and delivery that divides short and long term contracts for revenue recognition		6 months
Minimum number of months that long term contract may contain non-routine installations and special acceptance protocols in months		6 months
Capitalization of software development costs		$ 5,167,000	$ 2,900,000	$ 3,637,000
Foreign currency transaction gain (loss), before tax		104,000	(2,499,000)	(1,567,000)
Amortization expense on capitalized computer software		30,000	892,000	892,000
Goodwill impairment		0	0
Impairment of intangible assets		$ 0	0
Number of reporting units | reporting_unit		3
Goodwill	$ 369,762,000	$ 369,275,000	369,762,000	369,700,000
Utilizing discount rate	10.00%
Perpetual growth rate, percentage		3.00%
Number of previous months historical warranty claims used to calculate warranty expense percentage		12 months
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percent fair value is less than carrying amount		50.00%
Life of warranty obligations for sales that include installation services, in months		12 months
Product obligation period from date of purchase, in months		12 months
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Life of warranty obligations for sales that include installation services, in months		24 months
Product obligation period from date of purchase, in months		24 months
Research And Development [Member]
Summary Of Significant Accounting Policies [Line Items]
Capitalization of software development costs		$ 1,803,000	2,046,000
Test [Member]
Summary Of Significant Accounting Policies [Line Items]
Goodwill	$ 25,109,000	24,631,000	$ 25,109,000	$ 25,022,000
Sensors [Member]
Summary Of Significant Accounting Policies [Line Items]
Goodwill		1,466,000
PCB Group, Inc [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of fair value in excess of carrying amount	11.00%		11.00%
Goodwill		$ 343,178,000
Increase in discount rate, percentage		0.50%
Decrease in estimated perpetual sales growth rate, percentage		0.50%