Other non operating income expense excluding disposal group not discontinued operation gain loss on disposal.

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Restructuring and other charges.

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Transaction costs.

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The amount of amortization of deferred charges applied against earnings during the period.

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Amount of deprecation and amortization expense attributable to property, plant and equipment and intangible assets of discontinued operations.

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Amount of other expense attributable to disposal group, including, but not limited to, discontinued operation.

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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 of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

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The net result for the period of deducting operating expenses from operating revenues.

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Amount of expense classified as other.

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Amount 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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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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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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Segment Information - Schedule of Total Revenues, Segment Operating Profit and Total Asset for Reporting Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Dec. 29, 2017	Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Segment Reporting Information [Line Items]
Total Segment Operating Profit	$ 99,086	$ 89,954	$ 102,681	$ 113,130	$ 160,846	$ 162,512	$ 68,755	$ (4,670)	$ 404,851	$ 387,443	$ 244,142
Restructuring and Other Charges							(130,300)		(337,066)	(153,951)	(91,648)
Total Other (Expense) Income, net									(53,892)	(56,462)	(988)
Earnings from Continuing Operations Before Taxes	$ 53,537	$ 93,399	$ 111,832	$ 92,191	$ 142,400	$ 146,633	$ 48,651	$ (6,703)	350,959	330,981	243,154
Restructuring charges excluded segment profit									311,470
Other expense income									14,800	25,600	29,100
Intangibles amortization									79,100	68,100	46,100
Intangible assets									79,098	80,731	46,095
Gain related to litigation settlement									35,000
Revenue from related parties									35,400	64,800
CH2M HILL Companies, Ltd.
Segment Reporting Information [Line Items]
Transaction Costs									(18,169)	(80,436)	(17,100)
Restructuring charges excluded segment profit									311,332	190,806	135,438
Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit									1,024,437	783,618	463,124
Corporate Non Segment
Segment Reporting Information [Line Items]
Other Corporate Expenses									(264,351)	(161,788)	(110,234)
Corporate Non Segment \| CH2M HILL Companies, Ltd.
Segment Reporting Information [Line Items]
Restructuring charges excluded segment profit									184,646	77,148	42,781
Critical Mission Solutions \| Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit									310,043	255,718	197,196
Litigation expenses included in segment profit										15,000
People & Places Solutions \| Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit									714,394	527,900	265,928
Restructuring charges excluded segment profit											$ 23,800
Other Expense \| CH2M HILL Companies, Ltd.
Segment Reporting Information [Line Items]
Amortization of deferred financing fees									$ 3,200	$ 1,800