LONG-TERM DEBT - Summary of Loan Tranches (Details) - Schuldschein Loan - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt	$ 98,671	$ 0
March 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.32%
Long-term debt	$ 2,630
December 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.04%
Long-term debt	$ 21,110
March 2021
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.07%
Long-term debt	$ 14,770
March 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.00%
Long-term debt	$ 21,110
Euribor 6 Months \| March 2019
Debt Instrument [Line Items]
Debt instrument basis points spread on variable rate	1.30%
Long-term debt	$ 15,831
Euribor 6 Months \| March 2021
Debt Instrument [Line Items]
Debt instrument basis points spread on variable rate	1.65%
Long-term debt	$ 23,220

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

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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.

+ References

No definition available.

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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