GOODWILL AND INTANGIBLE ASSETS - Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Changes in the carrying amount of goodwill, by operating segment
Balance at the beginning of the period	$ 62,873	$ 45,077
Acquisitions	1,097	26,986
Deconsolidation of Subsidiary		(1,698)
Impairment	0	(7,492)
Goodwill, Gross	63,970	70,365
Accumulated impairment		(7,492)
Balance at the end of the period	63,970	62,873
U.S. Telecom
Changes in the carrying amount of goodwill, by operating segment
Balance at the beginning of the period	35,268	39,639
Acquisitions		3,121
Impairment		(7,492)
Goodwill, Gross	35,268	42,760
Accumulated impairment		(7,492)
Balance at the end of the period	35,268	35,268
International
Changes in the carrying amount of goodwill, by operating segment
Balance at the beginning of the period	24,326	5,438
Acquisitions	1,097	20,586
Deconsolidation of Subsidiary		(1,698)
Goodwill, Gross	25,423	24,326
Balance at the end of the period	25,423	24,326
Renewable Energy
Changes in the carrying amount of goodwill, by operating segment
Balance at the beginning of the period	3,279
Acquisitions		3,279
Goodwill, Gross	3,279	3,279
Balance at the end of the period	$ 3,279	$ 3,279

Amount of divestiture of an asset representing future economic benefits arising from deconsolidation of subsidiary.

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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- Definition

Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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- Definition

Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267

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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 28
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-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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