Revenue Recognition- Summary of Revenues (Detail) - Sales Revenue, Net [Member] - Revenue from Rights Concentration Risk [Member]	12 Months Ended
	Dec. 30, 2022	Dec. 31, 2021	Jan. 01, 2021
Time And Materials Contracts [Member]
Disaggregation Of Revenue [Line Items]
Fiscal Years	79.00%	78.00%	80.00%
Time And Materials Contracts [Member] | Engineering and Other Scientific [Member]
Disaggregation Of Revenue [Line Items]
Fiscal Years	63.00%	61.00%	61.00%
Time And Materials Contracts [Member] | Environmental and Health [Member]
Disaggregation Of Revenue [Line Items]
Fiscal Years	16.00%	17.00%	19.00%
Fixed Price Contracts [Member]
Disaggregation Of Revenue [Line Items]
Fiscal Years	21.00%	22.00%	20.00%
Fixed Price Contracts [Member] | Engineering and Other Scientific [Member]
Disaggregation Of Revenue [Line Items]
Fiscal Years	20.00%	21.00%	19.00%
Fixed Price Contracts [Member] | Environmental and Health [Member]
Disaggregation Of Revenue [Line Items]
Fiscal Years	1.00%	1.00%	1.00%