COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Annual minimum payments due
2018	$ 7,886
2019	8,089
2020	7,570
2021	5,245
2022	5,366
2023 through 2028	19,577
Total	53,733
Rent expense	7,500	$ 6,000	$ 5,700
Deferred rent	6,800	$ 8,600
Leasehold Improvements, Gross	5,600
Purchase Obligation	$ 300

For a classified balance sheet, the cumulative difference between the rental income or payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense, by the lessor or lessee, respectively, more than one year after the balance sheet date.

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 210.5-02.26(c))
-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
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39927-112707

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This item represents the deferred credit for an incentive or inducement received by a lessee from a lessor, in order to motivate the lessee to enter the lease agreement, which incentive or inducement is to be recognized as a reduction of rental expense over the lease term.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due 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 required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth 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.

+ References

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due 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 required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due 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 required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due 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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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth 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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Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

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-Publisher FASB
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Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

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