Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		60 Months Ended
	Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015	Sep. 30, 2015
Income Tax Disclosure [Line Items]
Effective income tax rate	537.00%	3.00%	(9.00%)	(1.00%)
Income before income taxes	$ (704)	$ 17,939	$ (23,819)	$ 52,734
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	(9,000)	$ (6,000)	(16,000)	(14,000)
Deferred Other Tax Expense (Benefit)				(1,400)
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount			(2,600)	(2,100)
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions				$ (3,100)
Unrecognized tax benefits	15,500		15,500		$ 14,100
Income tax provision upon recognition of unrecognized tax benefit	13,900		13,900
Unrecognized tax benefits that would impact valuation allowance	4,800		4,800
Potentail reduction in unrecognized tax benefits and accrued interest over next 12 months	$ (5,000)		$ (5,000)
Korea (South), Won
Income Tax Disclosure [Line Items]
Income Tax Examination, Description					12