LONG-TERM DEBT. (Details)			12 Months Ended
	Jun. 28, 2013 USD ($)	Dec. 19, 2012 USD ($)	Dec. 26, 2015 USD ($) item	Nov. 19, 2015 USD ($)	Dec. 27, 2014 USD ($) item	Aug. 27, 2014 $ / shares	Aug. 09, 2013 USD ($)	Apr. 29, 2013 USD ($)
Long-term debt.
Less, current maturities			$ 666,668		$ 666,668
Long-term debt			7,666,665		$ 8,333,330
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
Credit Agreement | Wells Fargo | Prime rate
Long-term debt.
Effective interest rate (as a percent)			2.79%		2.50%
Credit Agreement | Wells Fargo | Maximum
Long-term debt.
Issuance of special dividend				$ 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
Long-term debt.
Variable interest rate basis			prime rate
Revolving credit facility | Wells Fargo | LIBOR
Long-term debt.
Variable interest rate basis			LIBOR
Revolving credit facility | Wells Fargo | Alternate base rate
Long-term debt.
Variable interest rate basis			Federal funds rate plus 0.50%
Revolving credit facility | Wells Fargo | Federal funds rate
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 | LIBOR
Long-term debt.
Basis spread on variable interest rate basis (as a percent)			1.50%
Revolving credit facility | Wells Fargo | Minimum | Alternate base rate
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 | LIBOR
Long-term debt.
Quarterly commitment fee (as a percent)			2.50%
Revolving credit facility | Wells Fargo | Maximum | Alternate base rate
Long-term debt.
Basis spread on variable interest rate basis (as a percent)			1.50%
Term loan
Long-term debt.
Outstanding amount			$ 8,333,333		8,999,998
Term loan | Interest rate swap | Cash flow
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
2016			666,668
2017			7,666,665
Letter Of Credit
Maturities of long-term debt
Aggregate outstanding amount			$ 2,300,000		$ 3,300,000