Pension Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2017	Sep. 24, 2016	Sep. 26, 2015
Change in benefit obligation:
Benefit obligation at beginning of period	$ 104,667	$ 98,482
Interest cost	2,559	3,401	$ 3,879
Actuarial (gain)/loss	300	19,658
Benefits paid	(4,827)	(2,617)
Foreign currency translation adjustments	3,178	(14,257)
Benefit obligation at end of period	105,877	104,667	98,482
Change in plan assets:
Fair value of plan assets at beginning of period	96,692	93,605
Actual gain on plan assets	3,596	15,840
Employer contributions	3,280	3,415
Benefits paid	(4,827)	(2,617)
Foreign currency translation adjustments	3,713	(13,551)
Fair value of assets at end of period	102,454	96,692	$ 93,605
Amount recognized in the consolidated balance sheets:
Unfunded status (non-current)	(3,423)	(7,975)
Net amount recognized	$ (3,423)	$ (7,975)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

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Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

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Amount of cost recognized for passage of time related to defined benefit plan.

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Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of foreign currency translation gain (loss) which increases (decreases) plan assets of defined benefit plan.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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