NOTES PAYABLE AND AMENDED CREDIT AGREEMENT - Summary of Notes Payable and Credit Agreement (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Debt Instruments [Abstract]
Payments/Long term debt, Total	$ 30,582	$ 39,836
Less current portion	(1,066)	(1,434)
Long term portion	29,516	38,402
Credit Facility [Member]
Debt Instruments [Abstract]
Payments/Long term debt, Total	$ 29,000	38,000
Average effective interest rate	4.40%
3.25% through 5.50% Notes Payable due in Next Year [Member]
Debt Instruments [Abstract]
Payments/Long term debt, Total	$ 1,582	$ 1,836
Annual installments	$ 1,066
3.25% through 5.50% Notes Payable due in Next Year [Member] \| Minimum [Member]
Debt Instruments [Abstract]
Percentage of interest accrued	3.25%
3.25% through 5.50% Notes Payable due in Next Year [Member] \| Maximum [Member]
Debt Instruments [Abstract]
Percentage of interest accrued	5.50%

Amount of the total principal payments made during the annual reporting period.

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

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The effective interest rate during the reporting period.

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

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