Restructuring and Related Costs Restructuring and Related Costs (Restructuring Reserve Rollforward) (Details) - USD ($)	3 Months Ended
	Dec. 29, 2018	Dec. 30, 2017
2018 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring expense	$ 0	$ 0
Test & Simulation
Restructuring Reserve [Roll Forward]
Restructuring expense	130,000	$ 255,000
Test & Simulation | 2018 Restructuring Plan
Restructuring Reserve [Roll Forward]
Balance, September 29, 2018	1,051,000
Restructuring expense	0
Payments	(1,010,000)
Other adjustments	0
Currency translation	0
Balance, December 29, 2018	41,000
Test & Simulation | 2017 Restructuring Plan
Restructuring Reserve [Roll Forward]
Balance, September 29, 2018	2,933,000
Restructuring expense	130,000
Payments	(2,789,000)
Other adjustments	0
Currency translation	0
Balance, December 29, 2018	$ 274,000