Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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In a business combination in which the amount of net identifiable assets acquired and liabilities assumed exceeds the aggregate consideration transferred or to be transferred (as defined), this element represents the amount of gain recognized by the entity.

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ACQUISITIONS (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
ACQUISITIONS (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020	Jun. 30, 2021
Business Acquisition
Goodwill	$ 320,256	$ 320,256	$ 266,737
Business Combination, Acquisition Related Costs	$ 0	$ 800
Minetuff Dewatering Pumps Australiz Pty Ltd
Business Acquisition
Business acquisition, percentage of voting interests acquired	100.00%	100.00%
Total purchase price		$ 13,700
Puronics, Inc.
Business Acquisition
Business acquisition, percentage of voting interests acquired				100.00%
New Aqua, LLC
Business Acquisition
Business acquisition, percentage of voting interests acquired				100.00%
Atlantic Turbine Pump, LLC
Business Acquisition
Business Combination, Bargain Purchase, Gain Recognized, Amount		500
Puronics Inc., New Aqua LLC, Power Integrity Services, LLC, and Atlantic Turbine Pump LLC
Business Acquisition
Total purchase price		185,100
Puronics Inc., New Aqua LLC, Power Integrity Services, LLC, and Atlantic Turbine Pump LLS
Business Acquisition
Intangible assets	$ 121,400	121,400
Goodwill	55,500	55,500
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 52,100	52,100
Business Acquisition, Pro Forma Revenue		42,900	$ 102,400
Gicon Pumps & Equipment, Inc.
Business Acquisition
Business acquisition, percentage of voting interests acquired			100.00%
Business Combination, Bargain Purchase, Gain Recognized, Amount		5,600
Total purchase price		28,100
Waterite, Inc. and Waterite America, Inc.
Business Acquisition
Business acquisition, percentage of voting interests acquired			100.00%
Total purchase price		$ 21,900
Minimum \| Puronics Inc., New Aqua LLC, Power Integrity Services, LLC, and Atlantic Turbine Pump LLS
Business Acquisition
Acquired intangible assets useful life		12 years
Maximum \| Puronics Inc., New Aqua LLC, Power Integrity Services, LLC, and Atlantic Turbine Pump LLS
Business Acquisition
Acquired intangible assets useful life		20 years