Postretirement Benefits Schedule of Net Funded Status and APBO (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 30, 2018	Dec. 31, 2017	Jan. 01, 2017
Defined Benefit Plan [Abstract]
Benefit obligation at beginning of year	$ 4,838	$ 4,566
Service cost	196	192	$ 150
Interest cost	178	191	165
Plan participants' contributions	97	88
Plan participants' contributions	97	88
Actuarial loss (gain)	(894)	(122)
Benefits paid	(99)	(115)
Benefits paid	(99)	(115)
Medicare part D prescription drug subsidy	4	38
Benefit obligation at end of year	4,320	4,838	4,566
Fair value of plan assets at beginning of year	0	0
Employer contributions	(2)	(11)
Funded status	(4,320)	(4,838)
Fair value of plan assets at end of year	$ 0	$ 0	$ 0
Discount rate used to determine benefit obligations	4.17%	3.60%
Discount rate used to determine net periodic benefit cost	3.60%	4.11%
Defined Benefit Plan, Plan Assets, Prescription Drug Subsidy Receipt	$ 4	$ 38

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- Definition

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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Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964

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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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Amount of contributions received by defined benefit plan from participant which increase benefit obligation.

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Amount, before benefit payment, of receipt from prescription drug subsidy which increases benefit obligation of defined benefit postretirement plan.

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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 funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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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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-Publisher FASB
-Name Accounting Standards Codification
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Amount of contributions received by defined benefit plan from participant which increases plan assets.

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Amount of receipt from prescription drug subsidy which increases plan assets of defined benefit postretirement plan.

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

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