Long-Term Debt (Details) (USD $)	3 Months Ended
	Mar. 30, 2013	Dec. 29, 2012
Long-term debt and line of credit
Long-term debt	$ 16,632,000	$ 8,543,000
Less current portion of long-term debt	(2,770,000)	(1,646,000)
Long-term debt, less current portion	13,862,000	6,897,000
Outstanding credit facility		10,117,000
Accumulated depreciation on the capital lease assets	29,708,000	28,524,000
Equipment term loan due monthly through March 2020
Long-term debt and line of credit
Long-term debt	8,500,000
Stated interest rate (as a percent)	2.69%
Number of manufacturing facilities containing equipment used to secure credit	3
Bluffton, IN mortgage loan due monthly through December 2016
Long-term debt and line of credit
Long-term debt	1,979,000	2,000,000
Variable rate basis	30 day LIBOR
Basis points added to base rate (as a percent)	1.65%
Bluffton, IN mortgage loan due monthly through December 2016 | Cash flow hedge
Long-term debt and line of credit
Fixed interest rate through swap agreement (as a percent)	6.85%
Interest Rate Cash Flow Hedges
Notional value of interest rate swap	2,000,000
Fair value of interest rate swap	300,000
Lynden, WA equipment term loan due monthly through May 2014
Long-term debt and line of credit
Long-term debt	1,071,000	1,286,000
Variable rate basis	LIBOR
Basis points added to base rate (as a percent)	1.65%
Lynden, WA real estate term loan due monthly through July 2017
Long-term debt and line of credit
Long-term debt	2,974,000	3,028,000
Variable rate basis	LIBOR
Basis points added to base rate (as a percent)	1.65%
Lynden, WA real estate term loan due monthly through July 2017 | Cash flow hedge
Long-term debt and line of credit
Fixed interest rate through swap agreement (as a percent)	4.28%
Interest Rate Cash Flow Hedges
Notional value of interest rate swap	3,100,000
Fair value of interest rate swap	400,000
Capital Lease Obligations, primarily due September 2017
Long-term debt and line of credit
Long-term debt	2,108,000	2,229,000
Amount of equipment held under capital lease	3,500,000
Accumulated depreciation on the capital lease assets	900,000	800,000
Revolving line of credit
Long-term debt and line of credit
Variable rate basis	30-day LIBOR
Maximum borrowing capacity	30,000,000
Outstanding credit facility	0
Borrowing availability	$ 20,100,000
Revolving line of credit | Minimum
Long-term debt and line of credit
Basis points added to base rate (as a percent)	1.125%
Revolving line of credit | Maximum
Long-term debt and line of credit
Basis points added to base rate (as a percent)	1.75%
New term loans | Minimum
Long-term debt and line of credit
Minimum asset coverage ratio	1.75
Minimum fixed charge coverage ratio	1.2
New term loans | Maximum
Long-term debt and line of credit
Maximum leverage ratio under the New Loan Agreement	3.25
Maximum leverage ratio under the Prior Agreement	3.0