IMPACT OF THE INVASION OF UKRAINE (Narrative) (Details) - USD ($)	3 Months Ended				6 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Mar. 04, 2022
Unusual or Infrequent Item, or Both [Line Items]
Property and equipment, net		$ 255,772,000			$ 255,772,000		$ 273,348,000
Operating lease, right-of-use asset		145,844,000			145,844,000		148,780,000
Commitments related to operating lease agreements that have not yet commenced		14,500,000			14,500,000
Impairment charges					659,000	$ 21,002,000
Bad debt expense					2,031,000	11,748,000
Forecast | Discontinued Operations, Disposed of by Sale
Unusual or Infrequent Item, or Both [Line Items]
Loss on sale of holdings	$ 18,400,000
Humanitarian Commitment
Unusual or Infrequent Item, or Both [Line Items]
Commitments related to operating lease agreements that have not yet commenced		45,200,000			45,200,000
Nonoperating expense		3,900,000	$ 34,000,000		10,000,000	8,400,000
Humanitarian Commitment | Cost of revenues (exclusive of depreciation and amortization)
Unusual or Infrequent Item, or Both [Line Items]
Nonoperating expense		2,900,000	3,300,000		5,300,000	22,400,000
Humanitarian Commitment | Selling, general and administrative expenses
Unusual or Infrequent Item, or Both [Line Items]
Nonoperating expense		1,000,000	5,100,000		4,700,000	11,600,000
Ukraine
Unusual or Infrequent Item, or Both [Line Items]
Property and equipment, net		67,721,000			67,721,000		$ 70,183,000
Operating lease, right-of-use asset		9,700,000			9,700,000
Ukraine | Cost of revenues (exclusive of depreciation and amortization)
Unusual or Infrequent Item, or Both [Line Items]
Standby resources expense		2,000,000	9,300,000		9,400,000	11,800,000
Ukraine | Selling, general and administrative expenses
Unusual or Infrequent Item, or Both [Line Items]
Standby resources expense		200,000	$ 14,400,000		400,000	33,100,000
Ukraine | Other income/(expense)
Unusual or Infrequent Item, or Both [Line Items]
Impairment charges						1,300,000
Ukraine | Humanitarian Commitment
Unusual or Infrequent Item, or Both [Line Items]
Commitments related to operating lease agreements that have not yet commenced								$ 100,000,000
Russia
Unusual or Infrequent Item, or Both [Line Items]
Impairment of property, plant and equipment				$ 15,100,000
Operating lease, impairment loss				3,800,000
Goodwill, impairment loss				$ 700,000
Bad debt expense						$ 8,200,000
Building | Ukraine
Unusual or Infrequent Item, or Both [Line Items]
Property and equipment, net		51,500,000			51,500,000
Computer Equipment | Ukraine
Unusual or Infrequent Item, or Both [Line Items]
Property and equipment, net		9,500,000			9,500,000
Furniture and Fixtures | Ukraine
Unusual or Infrequent Item, or Both [Line Items]
Property and equipment, net		5,100,000			5,100,000
Leasehold Improvements | Ukraine
Unusual or Infrequent Item, or Both [Line Items]
Property and equipment, net		$ 1,600,000			$ 1,600,000