Restructuring and Related Costs (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 735	$ 92	$ 1,343	$ 1,036
2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Cost incurred to date	4,262		4,262
Restructuring and related cost, expected cost	2,000		2,000
2014 Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	0	0	0
Machida, Japan | 2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	$ 92	0	$ 1,036
Cost incurred to date	1,964		1,964
Employee Severance | 2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	715		1,129
Cost incurred to date	4,028		4,028
Employee Severance | Machida, Japan | 2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges			3
Cost incurred to date	133		133
Expected cost remaining	40		40
Employee Severance | Machida, Japan | 2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Cost incurred to date	1,444		1,444
Facility Closing | 2017 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	24		211
Cost incurred to date	234		234
Facility Closing | Machida, Japan | 2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Cost incurred to date	$ 520		$ 520