Benefit Plans - Fair Value Measurement of Plan Assets (Details) $ in Thousands	12 Months Ended
Dec. 26, 2020 USD ($)
Change in benefit obligation:
Fair value of plan assets at beginning of year	$ 78,502
Fair value of plan assets at end of year	100,478
Level 3
Change in benefit obligation:
Fair value of plan assets at beginning of year	609
Bulk annuity contract added during the year	53,093
Actual return on plan assets	76
Fair value of plan assets at end of year	$ 53,778

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(01)
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- Definition

Amount, measured using unobservable input, of increase in plan asset of defined benefit plan from purchase.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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- Details

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