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Summary of Significant Accounting Policies - Revenue Recognition and Allowances for Accounts Receivable and Unbilled Services (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenue Recognition
Cumulative effect of a change in accounting principle	$ 209,019	$ 197,751	$ 196,472	$ 207,229
Retained Earnings
Revenue Recognition
Cumulative effect of a change in accounting principle	$ 216,999	200,249	$ 186,229	169,390
Cumulative Effect Period of Adoption, Adjustment | ASC 606
Revenue Recognition
Cumulative effect of a change in accounting principle				366
Cumulative Effect Period of Adoption, Adjustment | ASC 606 | Retained Earnings
Revenue Recognition
Cumulative effect of a change in accounting principle				$ 366
Cumulative Effect Period of Adoption, Adjustment | ASC 326
Revenue Recognition
Cumulative effect of a change in accounting principle		(203)
Cumulative Effect Period of Adoption, Adjustment | ASC 326 | Retained Earnings
Revenue Recognition
Cumulative effect of a change in accounting principle		$ (203)
Minimum
Revenue Recognition
Period in which engagements are generally completed (months)	3 months
Maximum
Revenue Recognition
Period in which engagements are generally completed (months)	6 months

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Represents the period in which engagements of the entity are completed.

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 810
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