GOODWILL AND LONG-LIVED ASSETS - Long-lived Assets Impairment (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		$ 10,883
Right-of-use assets - operating leases, net		10,494
Intangible assets, net		103
Other non-current assets		871
Total long-lived assets	$ 0	22,351
Furniture and fixtures
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		413
Leasehold improvements
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		2,806
Office equipment
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		198
Purchased software
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		14
Computer hardware
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		2,842
Right-of-use assets - finance leases, net
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		1,318
Capitalized software
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		304
Internally-developed software
Impaired Long-Lived Assets Held and Used [Line Items]
Tangible asset impairment		$ 2,988

Asset Impairment Charges, Excluding Goodwill Impairment

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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Amount of loss from impairment of right-of-use asset from operating lease.

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