FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Carrying Value
Fair value measurements
Long-term debt	$ 159,700	$ 156,800
Significant Other Observable Inputs (Level 2) \| Estimated Fair Value
Fair value measurements
Long-term debt	163,200	159,900
Recurring basis
Fair value measurements
Total assets measured at fair value	63,666	68,636
Recurring basis \| Certificate of deposit
Fair value measurements
Certificates of deposit	391	391
Recurring basis \| Money market funds
Fair value measurements
Investments	3,563	29,027
Recurring basis \| Short Term Investments
Fair value measurements
Investments	7,755	9,237
Recurring basis \| Commercial Paper
Fair value measurements
Investments	49,957	29,981
Recurring basis \| Contingent Consideration
Fair value measurements
Investments	2,000
Recurring basis \| Quoted Prices in Active Markets (Level 1)
Fair value measurements
Total assets measured at fair value	3,825	30,778
Recurring basis \| Quoted Prices in Active Markets (Level 1) \| Money market funds
Fair value measurements
Investments	3,563	29,027
Recurring basis \| Quoted Prices in Active Markets (Level 1) \| Short Term Investments
Fair value measurements
Investments	262	1,751
Recurring basis \| Significant Other Observable Inputs (Level 2)
Fair value measurements
Total assets measured at fair value	57,841	37,858
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Certificate of deposit
Fair value measurements
Certificates of deposit	391	391
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Short Term Investments
Fair value measurements
Investments	7,493	7,486
Recurring basis \| Significant Other Observable Inputs (Level 2) \| Commercial Paper
Fair value measurements
Investments	49,957	$ 29,981
Recurring basis \| Unobservable Inputs (Level 3)
Fair value measurements
Total assets measured at fair value	2,000
Recurring basis \| Unobservable Inputs (Level 3) \| Contingent Consideration
Fair value measurements
Investments	$ 2,000

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ 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(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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