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BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) € in Millions, $ in Millions			3 Months Ended		6 Months Ended
	May 31, 2023 USD ($)	Mar. 29, 2023 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) reportableSegment	Jun. 30, 2022 USD ($)	May 31, 2023 EUR (€)
Concentration Risk [Line Items]
Number of reportable segments \| reportableSegment					7
Straight-line revenue			$ 120.8	$ 113.3	$ 232.8	$ 222.7
Indian Customer
Concentration Risk [Line Items]
Deferral of revenue			$ 31.7		64.7
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Mexico Fiber
Concentration Risk [Line Items]
Total consideration		$ 252.5
Gain (loss) on sale		(80.0)			$ 78.9
Goodwill		$ 20.7
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Poland Unit
Concentration Risk [Line Items]
Total consideration	$ 7.2						€ 6.7
Gain (loss) on sale	$ 1.1
Common stock \| Data Centers \| U.S.
Concentration Risk [Line Items]
Controlling ownership interest percentage			0.72		0.72
ATC Europe
Concentration Risk [Line Items]
Ownership percentage			52.00%		52.00%
Joint Venture - Bangladesh Operations
Concentration Risk [Line Items]
Ownership percentage			51.00%		51.00%
Stonepeak \| Common stock \| Data Centers \| U.S.
Concentration Risk [Line Items]
Ownership percentage by noncontrolling owners			28.00%		28.00%
Stonepeak \| Preferred stock \| Data Centers \| U.S.
Concentration Risk [Line Items]
Ownership percentage by noncontrolling owners			100.00%		100.00%
Germany
Concentration Risk [Line Items]
Ownership percentage by noncontrolling owners			13.00%		13.00%
Germany \| ATC Europe
Concentration Risk [Line Items]
Ownership percentage			87.00%		87.00%
Spain
Concentration Risk [Line Items]
Ownership percentage by noncontrolling owners			17.00%		17.00%
Spain \| ATC Europe
Concentration Risk [Line Items]
Ownership percentage			83.00%		83.00%