GOODWILL (Goodwill Roll Forward) (Details) - USD ($) $ in Thousands	6 Months Ended	9 Months Ended
Jun. 30, 2020	Sep. 30, 2020
Goodwill [Roll Forward]
Balance as of January 1, 2020	$ 195,043	$ 195,043
Effect of net foreign currency exchange rate changes		(422)
Balance as of September 30, 2020		207,764
test IO
Goodwill [Roll Forward]
Purchase accounting adjustments	(226)	(226)
Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		311
2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		13,058
North America
Goodwill [Roll Forward]
Balance as of January 1, 2020	113,426	113,426
Effect of net foreign currency exchange rate changes		98
Balance as of September 30, 2020		120,842
North America \| test IO
Goodwill [Roll Forward]
Purchase accounting adjustments		863
North America \| Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		219
North America \| 2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		6,236
Europe
Goodwill [Roll Forward]
Balance as of January 1, 2020	80,873	80,873
Effect of net foreign currency exchange rate changes		(457)
Balance as of September 30, 2020		86,220
Europe \| test IO
Goodwill [Roll Forward]
Purchase accounting adjustments		(1,089)
Europe \| Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		71
Europe \| 2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		6,822
Russia
Goodwill [Roll Forward]
Balance as of January 1, 2020	$ 744	744
Effect of net foreign currency exchange rate changes		(63)
Balance as of September 30, 2020		702
Russia \| test IO
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Russia \| Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		21
Russia \| 2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		$ 0

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.

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-Publisher FASB
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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.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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