This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

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Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Restructuring and Other Charges - Summary of Restructuring and Other Activities by Major Type of Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 01, 2021	Oct. 02, 2020	Sep. 27, 2019
Restructuring Cost and Reserve [Line Items]
Gain on litigation settlement	$ 19,500
AWE ML
Restructuring Cost and Reserve [Line Items]
Impairment of equity method investment	(38,500)
CH2M HILL Companies, Ltd.
Restructuring Cost and Reserve [Line Items]
Restructuring costs	99,590	$ 324,183	$ 311,470
CH2M HILL Companies, Ltd. \| Lease Abandonments and Impairments
Restructuring Cost and Reserve [Line Items]
Restructuring costs	4,282	151,150	99,976
CH2M HILL Companies, Ltd. \| Voluntary and Involuntary Terminations
Restructuring Cost and Reserve [Line Items]
Restructuring costs	15,773	53,484	33,742
CH2M HILL Companies, Ltd. \| Outside Services
Restructuring Cost and Reserve [Line Items]
Restructuring costs	35,210	88,476	133,148
CH2M HILL Companies, Ltd. \| Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	44,325	$ 31,073	44,604
CH2M HILL Companies, Ltd. \| Other \| Other Expense
Restructuring Cost and Reserve [Line Items]
Gain on litigation settlement	$ (2,100)		$ 35,000