GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS - Rollfoward (Details) $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($)
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 734,607
Goodwill from AEP Acquisition	15,143
ETG and ELK Acquisition-related Working Capital Settlement	(15,600)
ETG and ELK Fair Value Adjustments During Measurement Period	15,143
Goodwill, Ending Balance	705,707
AEP
Goodwill [Roll Forward]
Goodwill from AEP Acquisition	(1,843)
ETG and ELK Fair Value Adjustments During Measurement Period	$ (1,843)

Business Acquisition, Provisional Accounting Incomplete, Adjustment, Working Capital Settlement

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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

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- Definition

Amount of increase (decrease) from adjustments after acquisition date under purchase accounting 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

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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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