Number Of Noncontributory Defined Benefit Pension Plans

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- Definition

Number Of Unfunded Healthcare And Life Insurance Benefit Plans

+ References

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- Definition

Number Of Unfunded Healthcare Plans For Benefits Prior To Medicare Eligibility

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of contributions expected to be received by defined benefit plan from employer in next fiscal year following latest fiscal year.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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- Definition

Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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-Publisher FASB
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Ultimate trend rate for health care cost for defined benefit postretirement plan.

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- Definition

Amount of cost for defined contribution plan.

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Employee Benefit Plans - Narrative (Details) $ in Millions	12 Months Ended
Employee Benefit Plans - Narrative (Details) $ in Millions	Dec. 28, 2019 USD ($) plan	Dec. 29, 2018 USD ($)	Dec. 30, 2017 USD ($)	Jan. 02, 2016 plan
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans	$ 11.7	$ 11.2	$ 9.3
Number of noncontributory defined benefit pension plans \| plan	2
Number of unfunded healthcare and life insurance benefit plans \| plan	2
Number of unfunded healthcare plans for benefits prior to medicare eligibility \| plan				1
Assumed health care cost trend rates	8.00%	8.00%
Assumed health care cost, grading	8.00%	8.00%
Expected contributions in 2020	$ 1.1
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans	$ 11.7	$ 11.2	$ 9.3
Assumed health care cost trend rates	8.00%	8.00%
Assumed health care cost, grading	8.00%	8.00%
Expected contributions in 2020	$ 1.1
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	30.00%
Equity Securities \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	30.00%
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	63.00%
Fixed Income Securities \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	63.00%
Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation	5.00%
Cash \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	5.00%
Precious metals
Defined Benefit Plan Disclosure [Line Items]
Target allocation	2.00%
Precious metals \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	2.00%