Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015
Income Taxes [Line Items]
Discrete tax benefit	$ 2,801,000	$ 2,283,000	$ 2,098,000
Effect tax rate percent excluding discrete tax Benefit	3.20%	19.30%	29.80%
Effective income tax rate	(9.00%)	18.00%	23.20%
Nondeductible PCB acquisition-related expense		$ 1,834,000
Tax adjustments, settlements, and unusual provisions			$ (1,836,000)
R&D tax credit carryover	$ 2,231,000	1,540,000
Foreign undistributed earnings	111,717,000	93,510,000
Unrecognized tax benefits that would affect the effective tax rate	3,234,000	3,429,000
Accrued interest related to uncertain income tax positions	404,000	519,000
Accrual for penalties related to uncertain tax positions	0	0
Current income tax receivable	5,392,000	3,238,000
Minnesota (R&D) [Member]
Income Taxes [Line Items]
R&D tax credit carryover	$ 2,231,000
R&D carryforward period	15 years
Germany And Japan [Member]
Income Taxes [Line Items]
Repatriation of foreign earnings, amount	$ 15,272,000	10,324,000
Effective income tax rate reconciliation, repatriation of foreign earnings, amount	11,000	$ 112,000	1,057,000
Germany, Japan, And Korea [Member]
Income Taxes [Line Items]
Repatriation of foreign earnings, amount			$ 9,194,000
PCB Group, Inc [Member]
Income Taxes [Line Items]
Deferred tax assets, tax credit carryforwards, other	$ 1,224,000