Note 4 - Accounts Receivable, Transit Accounts Receivable and Transit Accounts Payable (Details) - Accounts Receivable (USD $) In Thousands, unless otherwise specified	Sep. 27, 2014	Dec. 28, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for doubtful accounts and sales discounts	$ (1,000)	$ (978)
Accounts receivable, net	60,529	55,726
Billed Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, current	46,018	35,415
Unbilled Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, current	6,022	7,895
Work In Progress [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, current	$ 9,489	$ 13,394