Quarterly report pursuant to Section 13 or 15(d)

Revolving Credit Facility and Long-Term Debt - Additional Information (Detail)

v3.8.0.1
Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) - Agreement [Member] - USD ($)
3 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Line of Credit Facility [Line Items]          
Line of credit facility commitment fee description       The Agreement also provides for an unused commitment fee of 0.375% per year on the average daily unused amount of the revolving credit facility, as well as a fee of 1.75% of the face amount of each letter of credit reserved under the line of credit and 0.95% on standalone, fully secured letters of credit.  
Minimum [Member]          
Line of Credit Facility [Line Items]          
EBITDA       $ 25,000,000  
Ratio of restricted and unrestricted cash and marketable securities to workers' compensation and safety incentive liabilities       100.00%  
Maximum [Member]          
Line of Credit Facility [Line Items]          
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing       $ 1,000,000  
Scenario Forecast [Member] | Minimum [Member]          
Line of Credit Facility [Line Items]          
EBITDA $ 25,000,000 $ 25,000,000 $ 25,000,000    
Ratio of restricted and unrestricted cash and marketable securities to workers' compensation and safety incentive liabilities 100.00% 100.00% 100.00%    
Revolving Credit Facility Between March 15, 2018 and June 15, 2018 [Member] | Wells Fargo [Member]          
Line of Credit Facility [Line Items]          
Credit facility borrowing capacity       40,000,000  
Revolving Credit Facility Thereafter [Member] | Wells Fargo [Member]          
Line of Credit Facility [Line Items]          
Credit facility borrowing capacity       25,000,000  
Standby Letters of Credit [Member]          
Line of Credit Facility [Line Items]          
Credit facility borrowing used       5,900,000  
Standby Letters of Credit [Member] | Wells Fargo [Member]          
Line of Credit Facility [Line Items]          
Credit facility borrowing capacity       $ 6,000,000  
Revolving Credit Facility [Member]          
Line of Credit Facility [Line Items]          
Unused commitment fee on unused amount during period       0.375%  
Outstanding balance on term loan and revolving credit facility       $ 0 $ 0
Credit facility, expiration date       Jul. 01, 2018  
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 1.75%  
LIBOR plus rate       1.75%  
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 1.75%  
LIBOR plus rate       1.75%  
Line of Credit [Member]          
Line of Credit Facility [Line Items]          
Unused commitment fee on unused amount       1.75%  
Fully Secured Letter of Credit [Member]          
Line of Credit Facility [Line Items]          
Unused commitment fee on unused amount       0.95%  
Term Loan [Member]          
Line of Credit Facility [Line Items]          
Term loan from Bank, Interest rate description       One month LIBOR plus 2.00%  
Term loan with principal bank       $ 4,300,000 $ 4,400,000
Payment of monthly principal of term loan       $ 18,375  
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]          
Line of Credit Facility [Line Items]          
LIBOR plus rate       2.00%