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ACQUISITIONS (Other - Narrative) (Details) $ in Thousands, £ in Millions |  |  |  | 12 Months Ended
--- | --- | --- | --- | ---
Jun. 12, 2019 USD ($) | Nov. 08, 2018 USD ($) | Oct. 12, 2018 GBP (£) | Oct. 12, 2018 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Business Acquisition [Line Items] |  |  |  |  |  |  |
Cash paid for acquisitions, net of cash acquired |  |  |  |  | $ 437,556 | $ 418,369 | $ 47,768
Goodwill acquired |  |  |  |  | $ 267,804 | $ 329,938 |
Off Campus Partners |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Cash paid for acquisitions, net of cash acquired | $ 16,000 |  |  |  |  |  |
Initial payment for acquisition | 14,000 |  |  |  |  |  |
Goodwill acquired | 8,000 |  |  |  |  |  |
Estimated Fair Value | $ 9,000 |  |  |  |  |  |
Cozy Services Ltd |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Cash paid for acquisitions, net of cash acquired |  | $ 65,000 |  |  |  |  |
Goodwill acquired |  | 52,000 |  |  |  |  |
Estimated Fair Value |  | $ 11,000 |  |  |  |  |
Realla Ltd |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Cash paid for acquisitions, net of cash acquired |  |  | £ 12 | $ 15,000 |  |  |
Initial payment for acquisition |  |  | 10 | 13,000 |  |  |
Goodwill acquired |  |  | 8 | 10,000 |  |  |
Estimated Fair Value |  |  | £ 4 | $ 5,000 |  |  |

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