Summary of Gross Revenues and Reimbursements (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 03, 2014	Sep. 27, 2013	Jun. 28, 2013	Mar. 29, 2013	Dec. 28, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Jan. 03, 2014		Dec. 28, 2012		Dec. 30, 2011
Gross Revenues And Reimbursements [Line Items]
Gross revenues									$ 302,742		$ 298,818		$ 280,671
Less: Subcontractor fees									6,574		6,165		8,225
Revenues	72,772	75,231	75,505	72,660	72,946	73,298	74,484	71,925	296,168	[1]	292,653	[1]	272,446	[1]
Reimbursements:
Out-of-pocket reimbursements									6,619		6,426		6,162
Other outside direct expenses									9,506		19,665		19,617
Reimbursements									16,125		26,091		25,779
Revenues before reimbursements	$ 69,036	$ 70,096	$ 71,919	$ 68,992	$ 65,049	$ 66,725	$ 68,318	$ 66,470	$ 280,043		$ 266,562		$ 246,667

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