Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

Name:	us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

LONG-TERM DEBT, DERIVATIVES AND LETTERS OF CREDIT - Fair Value Totals and Balance Sheet Classification for Derivatives Designated as Hedges (Details) - Long-term debt - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	May 17, 2018
Designated as Hedging Instrument \| Net Investment Hedge
Derivatives, Fair Value [Line Items]
Fair value liability	$ (3,999)	$ (3,904)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Convertible debt embedded derivative liability			$ 45,400