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DEBT (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
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 |  |  |  |

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