Debt (Details)	12 Months Ended
Dec. 31, 2018 USD ($) instrument item	Dec. 31, 2017 USD ($)
Debt Instruments
Number of letters of credit issued \| item	3
Capital lease obligations	$ 5,125,000	$ 7,865,000
Letter Of Credit
Debt Instruments
Funds borrowed under Line of Credit	0
Credit Agreement
Debt Instruments
Borrowing, repaying and re-borrowing capacity	$ 20,000,000
Percentage of maximum borrowing capacity on eligible accounts receivable	80.00%
Percentage of maximum borrowing capacity on eligible core equipment	50.00%
Maximum borrowing capacity on core equipment	$ 12,500,000
Number of outstanding notes payable \| instrument	1
Interest rate (as a percent)	4.50%
Minimum tangible net worth	$ 100,000,000
Credit Agreement \| Term Note
Debt Instruments
Aggregate principal amount outstanding	$ 5,975,000
Credit Agreement \| Prime rate
Debt Instruments
Variable interest rate basis	prime rate
Credit Agreement \| Minimum
Debt Instruments
Ratio of current assets to current liabilities	1.50
Credit Agreement \| Minimum \| Prime rate
Debt Instruments
Interest rate (as a percent)	2.50%
Credit Agreement \| Maximum
Debt Instruments
Debt to tangible net worth ratio	1.00
Insurance Obligations
Debt Instruments
Letters of credit issued	$ 1,767,000
Workers' Compensation Insurance
Debt Instruments
Letters of credit issued	583,000
Performance Obligations
Debt Instruments
Letters of credit issued	75,000
Notes payable to commercial banks
Debt Instruments
Aggregate principal amount outstanding	$ 5,975,000
Interest rate (as a percent)	5.00%

Represents the ratio of current assets to current liabilities

No definition available.

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- Definition

Represents the ratio of debt to tangible net worth ratio to be maintained during the period.

+ References

No definition available.

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- Definition

Represents the maximum borrowing capacity of the second feature on the Line Of Credit.

+ References

No definition available.

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- Definition

Represents the number of letters of credit issued and outstanding.

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- Definition

The number of outstanding notes payable.

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- Definition

Represents the percentage of maximum borrowing capacity on eligible accounts receivable.

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- Definition

Represents the maximum percentage allowed to be borrowed against core equipment.

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- Definition

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

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No definition available.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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No definition available.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

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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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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- Definition

The lowest amount of net worth (total assets minus total liabilities) required by secondary market investors or state-imposed regulatory mandates.

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