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

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 contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

+ 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 (g)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 18
-URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

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- Definition

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

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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Employee Benefit Plans - Narrative (Details) $ in Millions	12 Months Ended
Employee Benefit Plans - Narrative (Details) $ in Millions	Dec. 31, 2022 USD ($) plan	Jan. 01, 2022 USD ($)	Jan. 02, 2021 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans	$ 12.1	$ 10.9	$ 12.1
Number of noncontributory defined benefit pension plans \| plan	2
Number of unfunded healthcare and life insurance benefit plans \| plan	2
Assumed health care cost trend rates	7.00%	7.00%
Assumed health care cost, grading	4.46%	4.75%
Healthcare & Life Ins
Defined Benefit Plan Disclosure [Line Items]
Expected contributions in next fiscal year	$ 0.5
Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Expense for defined contribution plans	$ 12.1	$ 10.9	$ 12.1
Assumed health care cost trend rates	7.00%	7.00%
Assumed health care cost, grading	4.46%	4.75%
Summit Materials, LLC \| Healthcare & Life Ins
Defined Benefit Plan Disclosure [Line Items]
Expected contributions in next fiscal year	$ 0.5
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	35.00%
Equity Securities \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	35.00%
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation	55.00%
Fixed Income Securities \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	55.00%
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%
Alternatives
Defined Benefit Plan Disclosure [Line Items]
Target allocation	4.00%
Precious metals
Defined Benefit Plan Disclosure [Line Items]
Target allocation	1.00%
Precious metals \| Summit Materials, LLC
Defined Benefit Plan Disclosure [Line Items]
Target allocation	1.00%