LONG-TERM DEBT. (Details) (USD $)	0 Months Ended						6 Months Ended											0 Months Ended
	Dec. 19, 2012 Amended And Restated Credit Agreement [Member] Wells Fargo [Member]	Jun. 28, 2014 Amended And Restated Credit Agreement [Member] Wells Fargo [Member] item	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member]	Dec. 28, 2013 Revolving Credit Facility [Member] Wells Fargo [Member]	Apr. 29, 2013 Revolving Credit Facility [Member] Wells Fargo [Member]	Dec. 19, 2012 Revolving Credit Facility [Member] Wells Fargo [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Prime Rate [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] London Interbank Offered Rate L I B O R [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Base Rate [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Debt Instrument Variable Rate Federal Funds Rate [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Minimum [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Minimum [Member] London Interbank Offered Rate L I B O R [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Minimum [Member] Base Rate [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Maximum [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Maximum [Member] London Interbank Offered Rate L I B O R [Member]	Jun. 28, 2014 Revolving Credit Facility [Member] Wells Fargo [Member] Maximum [Member] Base Rate [Member]	Aug. 09, 2013 Secured Debt [Member] Interest Rate Swap [Member] Cash Flow Hedging [Member]	Jun. 28, 2013 Secured Debt [Member] Wells Fargo [Member]	Jun. 28, 2014 Secured Debt [Member] Wells Fargo [Member]	Apr. 29, 2013 Secured Debt [Member] Wells Fargo [Member]	Dec. 19, 2012 Secured Debt [Member] Wells Fargo [Member]	Jun. 28, 2014 Letter Of Credit [Member]
Long-term debt.
Maximum borrowing capacity	$ 45,000,000					$ 35,000,000															$ 10,000,000
Term of credit agreement	5 years
Unused credit capacity under the agreement			31,300,000
Number of financial covenants to be complied with		3
Variable interest rate basis							prime rate	LIBOR	federal funds rate plus 0.50%	federal funds rate
Basis spread on variable interest rate basis (as a percent)										0.50%		1.50%	0.50%		2.50%	1.50%
Interest rate (as a percent)		2.48%
Quarterly commitment fee (as a percent)											0.20%			0.50%
Principal amount of debt			0	0																10,000,000
Amount of line of credit facility converted to term debt					10,000,000
Principal amount payable in quarterly installments																		166,667
Outstanding amount																			9,300,000
Notional amount																	5,000,000
Fixed interest rate (as a percent)																	3.10%
Aggregate outstanding amount																						$ 3,700,000