Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 29, 2014
Line of Credit Facility [Line Items]
Line of credit facility commitment fee description	The Agreement also provides for an unused commitment fee of 0.35% per year on the average dailyunused amount of the revolving credit facility, and a fee of 1.75% of the face amount of each letter of credit
Ratio of restricted and unrestricted cash and marketable securities to workers' compensation and safety incentive liabilities	1.0
Maximum amount of capital expenditures in 2015	5,000,000
Maximum amount of capital expenditures in 2016	4,000,000
Wells Fargo [Member]
Line of Credit Facility [Line Items]
Term loan payment due June 30, 2015	3,000,000
Term loan payment due September 30, 2015	7,000,000
Term loan payment due December 31, 2015	15,000,000
Term loan payment due June 30, 2016	5,000,000
Term loan payment due September 30, 2016	5,000,000
Minimum [Member]
Line of Credit Facility [Line Items]
Minimum Fixed Charge Coverage Ratio	1.5
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing	200,000
Maximum [Member]
Line of Credit Facility [Line Items]
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing	400,000
Cash dividend	0.22
Term Loan [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description	One month LIBOR plus 2.25%
LIBOR plus rate	2.25%
Term loan with principal bank	5,100,000
Payment of monthly installments of term loan	18,375
Term Loan [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		40,000,000
Term loan maturity date	Dec. 31, 2016
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description	One month LIBOR plus 4.0%
LIBOR plus rate	4.00%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Outstanding borrowings on the revolving credit facility	0
Unused commitment fee on unused amount	0.35%
Revolving Credit Facility [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		14,000,000
Revolving Credit Facility [Member] | Daily Floating Rate [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description	A daily floating rate of one month LIBOR plus 2%
LIBOR plus rate	2.00%
Revolving Credit Facility [Member] | Fixed Rate [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description	A fixed rate of LIBOR plus 2.0%
LIBOR plus rate	2.00%
Standby Letters of Credit [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		5,000,000
Cash-Secured Letters of Credit [Member]
Line of Credit Facility [Line Items]
Unused commitment fee on unused amount	175.00%
Cash-Secured Letters of Credit [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		114,300,000
Cash-Secured Letters of Credit [Member] | Wells Fargo [Member] | Certificate of Deposits [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	114,300,000
Credit facility non-refundable commitment fee	400,000