Earnings before interest taxes depreciation and amortization.

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Line of credit facility aggregate value of collateral accounts percent.

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Line of credit facility commitment fee percentage during period.

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Line of credit facility in use.

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Maximum amount to redeem retire repurchase or acquire stock upon agreement.

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Percentage of debt instrument collateral amount.

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Prohibition for purchase money financing on incurring additional indebtedness without the prior approval of the bank.

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Ratio of restricted and unrestricted cash and investments to workers compensation and claim liabilities measured quarterly basis.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount of assets pledged to secure a debt instrument.

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Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

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The contractual amount of dividends (or interest on participating income bonds) that must be paid for the current period (for example, unpaid cumulative dividends).

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Description of the fees for amounts available, but unused under the credit facility.

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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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Date the credit facility terminates, in CCYY-MM-DD format.

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The effective interest rate at the end of the reporting period.

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The effective interest rate during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of the required periodic payment applied to principal.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) - Agreement [Member] - USD ($)	1 Months Ended	3 Months Ended				12 Months Ended
	Jun. 30, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	May 14, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Credit facility borrowing used		$ 6,200,000				$ 6,200,000
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.
Outstanding balance on term loan and revolving credit facility		$ 0				$ 0		$ 0
Ratio of restricted and unrestricted cash and investments to workers' compensation and claim liabilities		1.00%	1.00%	1.00%	1.00%
Dividends or distributions paid						0
Maximum amount to redeem retire repurchase or acquire stock upon agreement						15,000,000
Minimum [Member]
Line of Credit Facility [Line Items]
EBITDA		$ 30,000,000	$ 30,000,000	$ 30,000,000	$ 30,000,000	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
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity			33,000,000.0				$ 50,000,000.0
Credit facility, expiration date						Jul. 01, 2022
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			$ 8,000,000.0
Line of Credit [Member]
Line of Credit Facility [Line Items]
Unused commitment fee on unused amount						1.75%
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, 2021
Percentage of initial fee under letter of credit	2.50%					2.50%
Percentage of aggregate fee under letter of credit						95.00%
Percentage of annual fee under letter of credit		1.00%				1.00%
Chubb Letter of Credit [Member] \| Collateral Accounts [Member]
Line of Credit Facility [Line Items]
Deposit in collateral accounts		$ 38,900,000				$ 38,900,000
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		$ 3,700,000				$ 3,700,000		$ 4,000,000.0
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%