| RELATED-PARTY TRANSACTIONS - Summary of Balance Sheet Assets and Liabilities from Related Parties (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020 | 
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| Related Party Transaction [Line Items] | ||
| Intangibles, net | $ 1,400 | $ 1,624 | 
| MGM | Marketing Agreement | ||
| Related Party Transaction [Line Items] | ||
| Intangibles, net | $ 1,000 | 1,000 | 
| Accrued liabilities | $ 20,000 | 
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- Definition Carrying amount as of the balance sheet date of obligations due all related parties. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition 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. No definition available. 
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