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Term of the interest rate that fluctuates over time as a result of an underlying benchmark interest rate or index.

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Refers to amortization period for deferred financing costs.

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Interest rate at which a bank borrows funds from other banks in the London interbank market.

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Refers to the mandatory amortization payment period.

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Refers to percentage of issued and outstanding shares of the capital stock of foreign subsidiaries given as collateralized security to line of credit.

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Amount of amortization expense attributable to debt issuance costs.

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

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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

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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 borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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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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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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DEBT (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
DEBT (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Jun. 19, 2014
Credit and Security Agreement [Abstract]
Deferred financing costs	$ 2,300	$ 1,800	$ 2,300
Debt issuance cost payment		0	2,012
Amortization of deferred financing costs		531	2,259
Scheduled principal payments [Abstract]
Total long-term debt	122,700	114,200	122,700
Less: Current maturities of long-term debt	(2,641)	(2,508)	(2,641)
Noncurrent portion of long-term debt	$ 120,053	$ 111,705	$ 120,053
KeyBank [Member]
Credit and Security Agreement [Abstract]
Interest rate on borrowings outstanding	3.38%	4.31%	3.38%
Effective LIBOR rate		2.56%	1.63%
Basis spread on variable rate		1.75%	1.75%
Interest expense incurred		$ 5,300	$ 6,800
Scheduled principal payments [Abstract]
2019		2,974
2020		5,948
2021		5,948
2022		101,118
Total long-term debt	$ 125,000	115,988	125,000
Less: Current maturities of long-term debt		(2,974)
Noncurrent portion of long-term debt		113,014
KeyBank [Member] \| Revolving Credit Facility [Member]
Credit and Security Agreement [Abstract]
Line of credit, amount outstanding	0	0	0
Unused borrowing capacity	75,000	$ 75,000	$ 75,000
KeyBank [Member] \| 2014 Credit and Security Agreement [Member]
Credit and Security Agreement [Abstract]
Deferred financing costs						$ 5,800
Deferred financing costs amortization period		5 years
KeyBank [Member] \| 2014 Credit and Security Agreement [Member] \| Revolving Credit Facility [Member]
Credit and Security Agreement [Abstract]
Maximum borrowing capacity				$ 50,000
KeyBank [Member] \| 2014 Credit and Security Agreement [Member] \| Term Loan [Member]
Credit and Security Agreement [Abstract]
Maximum borrowing capacity				145,000
KeyBank [Member] \| 2014 Credit and Security Agreement [Member] \| Delayed Draw Term Loan [Member]
Credit and Security Agreement [Abstract]
Maximum borrowing capacity				70,000
KeyBank [Member] \| 2016 Amendment [Member]
Credit and Security Agreement [Abstract]
Deferred financing costs					$ 500
Debt issuance cost payment				$ 700
KeyBank [Member] \| 2017 Amendment and Refinancing [Member]
Credit and Security Agreement [Abstract]
Debt issuance cost payment		$ 1,800
Line of credit facility, maturity date		Dec. 11, 2022
Mandatory amortization payment period		4 years
Amortization of deferred financing costs	$ 1,000
Percentage of capital stock of foreign subsidiaries given as collateralized security to line of credit		65.00%
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| LIBOR [Member]
Credit and Security Agreement [Abstract]
Basis spread on variable rate		1.00%
Term of variable rate		1 month
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| LIBOR [Member] \| Minimum [Member]
Credit and Security Agreement [Abstract]
Basis spread on variable rate		1.375%
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| LIBOR [Member] \| Maximum [Member]
Credit and Security Agreement [Abstract]
Basis spread on variable rate		2.75%
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| Federal Funds Rate [Member]
Credit and Security Agreement [Abstract]
Basis spread on variable rate		0.50%
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| Alternate Base Rate [Member] \| Minimum [Member]
Credit and Security Agreement [Abstract]
Basis spread on variable rate		0.375%
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| Alternate Base Rate [Member] \| Maximum [Member]
Credit and Security Agreement [Abstract]
Basis spread on variable rate		1.75%
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| Revolving Credit Facility [Member]
Credit and Security Agreement [Abstract]
Maximum borrowing capacity		$ 75,000
KeyBank [Member] \| 2017 Amendment and Refinancing [Member] \| Term Loan [Member]
Credit and Security Agreement [Abstract]
Maximum borrowing capacity		$ 125,000