Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Sep. 29, 2017	Dec. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for contract losses and doubtful accounts	$ (3,847)	$ (3,417)
Total accounts receivable, net	124,803	87,409
Billed accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable	90,263	60,510
Unbilled accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable	$ 38,387	$ 30,316