UNEARNED REVENUE (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Dec. 31, 2017 |
|
| Change in Contract with Customer, Liability [Roll Forward] | |||||
| Balance, beginning of period | $ 117,614 | $ 106,323 | $ 106,323 | ||
| Deferral of unearned revenue | 134,527 | 140,019 | |||
| Recognition of unearned revenue | $ 39,000 | $ 36,300 | 117,297 | $ 101,700 | 128,728 |
| Balance, end of period | 134,844 | 134,844 | 117,614 | ||
| Long-term unearned revenue | $ 10,900 | $ 10,900 | $ 8,600 | ||
| Long-term unearned revenue, recognition period (or less) | 5 years | ||||
| X | ||||||||||
- Definition Change in Contract with Customer, Liability [Roll Forward] No definition available.
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| X | ||||||||||
- Definition Contract With Customer, Liability, Recognition Period No definition available.
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| X | ||||||||||
- Definition Contract with Customer, Liability, Increase from Cash Receipts No definition available.
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| X | ||||||||||
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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