Quarterly report pursuant to Section 13 or 15(d)

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

v3.10.0.1
Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) - Agreement [Member] - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended
Jun. 30, 2018
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Sep. 30, 2018
Jul. 01, 2018
Dec. 31, 2017
Line of Credit Facility [Line Items]                
Credit facility borrowing used     $ 5,900,000     $ 5,900,000    
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 line, 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.    
Outstanding balance on term loan and revolving credit facility     $ 0     $ 0   $ 0
Ratio of restricted and unrestricted cash and marketable securities to workers' compensation and safety incentive liabilities     100.00% 100.00% 100.00%      
Line of credit facility dividend restrictions           the Company may not declare or pay any dividend in excess of $0.25 per share in total each fiscal quarter, subject to increase by no more than 10% each year beginning June 30, 2019, compared to the prior fiscal year    
Dividends, per share     $ 0.25     $ 0.25    
Dividend to be payable date           Jun. 30, 2019    
Scenario Forecast [Member]                
Line of Credit Facility [Line Items]                
Ratio of restricted and unrestricted cash and marketable securities to workers' compensation and safety incentive liabilities   100.00%            
Minimum [Member]                
Line of Credit Facility [Line Items]                
EBITDA $ 30,000,000   $ 30,000,000 $ 30,000,000 $ 30,000,000 $ 30,000,000    
Minimum [Member] | Scenario Forecast [Member]                
Line of Credit Facility [Line Items]                
EBITDA   $ 30,000,000            
Maximum [Member]                
Line of Credit Facility [Line Items]                
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing           $ 1,000,000    
Percentage of dividend payable           10.00%    
Revolving Credit Facility [Member]                
Line of Credit Facility [Line Items]                
Credit facility borrowing capacity             $ 28,000,000  
Credit facility, expiration date           Jul. 01, 2020    
Unused commitment fee on unused amount during period           0.375%    
Revolving Credit Facility [Member] | Daily Floating Rate [Member]                
Line of Credit Facility [Line Items]                
Term loan from Bank, Interest rate description           the 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           the fixed rate of LIBOR plus 1.75%    
LIBOR plus rate           1.75%    
Standby Letters of Credit [Member]                
Line of Credit Facility [Line Items]                
Credit facility borrowing capacity     $ 7,500,000     $ 7,500,000 $ 7,500,000  
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%    
Chubb Letter of Credit [Member]                
Line of Credit Facility [Line Items]                
Credit facility borrowing capacity $ 63,700,000     $ 63,700,000        
Credit facility, expiration date Jul. 01, 2019              
Percentage of initial fee under letter of credit           2.50%    
Percentage of aggregate fee under letter of credit           95.00%    
Percentage of annual fee under letter of credit     1.25%     1.25%    
Chubb Letter of Credit [Member] | Collateral Accounts [Member]                
Line of Credit Facility [Line Items]                
Percentage of deposit in collateral accounts           50.00%    
Chubb Letter of Credit [Member] | Collateral Accounts [Member] | Minimum [Member]                
Line of Credit Facility [Line Items]                
Deposit in collateral accounts     $ 16,000,000     $ 16,000,000    
Term Loan [Member]                
Line of Credit Facility [Line Items]                
Term loan from Bank, Interest rate description           one month LIBOR plus 2.0%    
Term loan with principal bank     $ 4,200,000     $ 4,200,000   $ 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%