Employee Benefit Plans (Narrative) (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	75.00%		50.00%
Employer matching pre-tax and Roth 401(k) contribution, percent	6.00%	6.00%	6.00%
Employer matching contributions	$ 4,967,000	$ 4,628,000	$ 2,732,000
Pretax amount recognized in other comprehensive income	996,000
Portion of accumulated comprehensive income recognized as component of net periodic benefit cost over the next fiscal year	524,000
Actuarial gain (loss)	$ 5,214,000	$ (6,123,000)
Discount rate	1.99%	1.28%
Discount rate calculation assumption, description	The discount rate is calculated based on zero-coupon bond yields published by the Deutsche Bundesbank for maturities that match the weighted average duration of the pension liability, adjusted for the average credit spread of corporate bond rates above the government bond yields.
Accumulated benefit obligation of the defined benefit retirement plan	$ 29,581,000	$ 30,716,000
Aggregate liabilities associated with other postretirement plans	4,585,000	4,508,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0	$ 0	$ 0
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee benefit plan target allocations	50.00%
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee benefit plan target allocations	50.00%