LONG-TERM DEBT. (Details)			12 Months Ended
	Jun. 28, 2013 USD ($)	Dec. 19, 2012 USD ($)	Dec. 31, 2016 USD ($) item	Nov. 16, 2016 USD ($)	Dec. 26, 2015 USD ($) item	Nov. 19, 2015 USD ($)	Aug. 27, 2014 $ / shares	Aug. 09, 2013 USD ($)	Apr. 29, 2013 USD ($)
Long-term debt.
Term loan facility			$ 7,195,105		$ 7,723,518
Less, debt issuance costs			304,895		609,815
Less, current maturities			7,195,105		361,748
Long-term debt					$ 7,361,770
Amended And Restated Credit Agreement | Wells Fargo
Long-term debt.
Maximum borrowing capacity		$ 45,000,000
Term of credit agreement		5 years
Unused credit capacity under the agreement			$ 35,000,000
Number of financial covenants to be complied with | item			3		3
Flat cash dividend limit of capital stock issued and outstanding (per share) | $ / shares							$ 0.03
Amended And Restated Credit Agreement | Wells Fargo | Prime Rate [Member]
Long-term debt.
Effective interest rate (as a percent)			3.05%		2.79%
Amended And Restated Credit Agreement | Wells Fargo | Maximum
Long-term debt.
Issuance of special dividend				$ 6,500,000		$ 6,500,000
Cash dividend limit as a percentage of consolidated net income						50.00%
Revolving Credit Facility | Wells Fargo
Long-term debt.
Maximum borrowing capacity			$ 35,000,000
Borrowings outstanding under credit facility			$ 0		$ 0
Amount of line of credit facility converted to term debt									$ 10,000,000
Revolving Credit Facility | Wells Fargo | Prime Rate [Member]
Long-term debt.
Variable interest rate basis			prime rate
Revolving Credit Facility | Wells Fargo | London Interbank Offered Rate L I B O R [Member]
Long-term debt.
Variable interest rate basis			LIBOR
Revolving Credit Facility | Wells Fargo | Base Rate [Member]
Long-term debt.
Variable interest rate basis			Federal funds rate plus 0.50%
Revolving Credit Facility | Wells Fargo | Debt Instrument Variable Rate Federal Funds Rate [Member]
Long-term debt.
Variable interest rate basis			federal funds rate
Basis spread on variable interest rate basis (as a percent)			0.50%
Revolving Credit Facility | Wells Fargo | Minimum
Long-term debt.
Quarterly commitment fee (as a percent)			0.20%
Revolving Credit Facility | Wells Fargo | Minimum | London Interbank Offered Rate L I B O R [Member]
Long-term debt.
Basis spread on variable interest rate basis (as a percent)			1.50%
Revolving Credit Facility | Wells Fargo | Minimum | Base Rate [Member]
Long-term debt.
Basis spread on variable interest rate basis (as a percent)			0.50%
Revolving Credit Facility | Wells Fargo | Maximum
Long-term debt.
Quarterly commitment fee (as a percent)			0.50%
Revolving Credit Facility | Wells Fargo | Maximum | London Interbank Offered Rate L I B O R [Member]
Long-term debt.
Basis spread on variable interest rate basis (as a percent)			2.50%
Revolving Credit Facility | Wells Fargo | Maximum | Base Rate [Member]
Long-term debt.
Basis spread on variable interest rate basis (as a percent)			1.50%
Term loan
Long-term debt.
Term loan facility			$ 7,500,000		8,333,333
Term loan | Interest Rate Swap | Cash Flow Hedging
Maturities of long-term debt
Notional amount								$ 5,000,000
Fixed interest rate (as a percent)								3.10%
Term loan | Wells Fargo
Long-term debt.
Maximum borrowing capacity		$ 10,000,000
Principal amount of debt									$ 10,000,000
Principal amount payable in quarterly installments	$ 166,667
Maturities of long-term debt
2017			7,500,000
Letter Of Credit | Other current assets
Maturities of long-term debt
Aggregate outstanding amount			$ 1,900,000		$ 2,300,000