Summary of Gross Revenues and Reimbursements (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2016	Sep. 30, 2016	Jul. 01, 2016	Apr. 01, 2016	Jan. 01, 2016	Oct. 02, 2015	Jul. 03, 2015	Apr. 03, 2015	Dec. 30, 2016		Jan. 01, 2016		Jan. 02, 2015
Gross Revenues And Reimbursements [Line Items]
Gross revenues									$ 322,293		$ 320,404		$ 313,723
Less: Subcontractor fees									7,217		7,572		9,019
Revenues	$ 77,013	$ 77,612	$ 77,295	$ 83,156	$ 73,681	$ 78,994	$ 79,864	$ 80,293	315,076	[1]	312,832	[1]	304,704	[1]
Reimbursements:
Out-of-pocket reimbursements									5,474		5,967		5,862
Other outside direct expenses									10,405		11,160		9,633
Reimbursements									15,879		17,127		15,495
Revenues before reimbursements	$ 72,753	$ 74,160	$ 73,334	$ 78,950	$ 69,789	$ 74,503	$ 75,272	$ 76,141	$ 299,197		$ 295,705		$ 289,209

[1] Geographic revenues are allocated based on the location of the client.